Okay, I know you won't want to hear this. But anyway....
While I will agree that your mom should have kept her comments to herself - she could be right. Your daughter is about 14 months old, right? Most respected child-care experts would not consider that to be "ready" for potty training - generally, more like 18 months, minimum. It's true that parents can sit a child on this age on the potty and possibly get results - but the child is not really "trained", as in recognising the signals that the body is giving. She's likely simply attempting to do what is expected - and honestly, twice is not really that big of a deal. Yes, it might be to you, and that's fine, but it doesn't mean that you have to expect everyone else to be just as excited.
Your child, your decision of course. But to an extent I can understand where your mom is coming from. I will probably become a grandma in the next five years or so, and TBH I'd find it kind of distressing if the parents were attempting potty-training so early. I would likely not say anything, but I'd be concerned. Grandparents are allowed to be concerned.
I just want to clarify something on this. In general, I would agree with you. However, I also believe that every child is unique and every child's abilities and self-awareness develop at a different pace.
My child is cloth diapered. As such, she has recognized a dirty diaper for several months now. Originally, the plan was never to potty train. It was to sit her on the potty once an evening (while I ran her bath) to get her comfortable with the chair. She tinkled the first time I sat her there. Then the second time. And the third time. Right now, she gets about 1/2 - 2/3 of her potties in the toilet, which is pretty stunning for a kid her age. But it did not take her long to associate the potty with it's proper use and get comfortable with it.
She tells me when she needs to go. She will say "uh-oh" and head to the bathroom. When we are out, she'll stop what she's doing and say "uh-oh" and pat her diaper. So we find somewhere and sit her down. Again, we get there in time about 1/2 the time, but she recognizes it and tells me "uh-oh" for a potty incident 100% of the time.
Other children may vary.
She caught a #2 in time today, which was a REALLY BIG DEAL, and that thrilled me and Mr. K to no end, especially as she had once again warned me with an "uh-oh" that something was coming.
^You may well be right on the training issue, but I'm absolutely certain from your posts on here that no matter what you thought privately with your future grandchild you wouldn't be as openly disbelieving/hostile as Knitterly's mother. I'm sure in the future should I become a grandmother I'll think that DDs are doing some things 'wrong', but I hope that it doesn't come to the point that I've driven them away with my negativity, which seems to be what's happening here.
If my daughters were attempting to train their hypothetical children using punishments or shame then I may feel the need to speak up, but if I just thought it was a bit early and it turned out I was right and after a few times it didn't work I wouldn't say anything other than "Oh, you've decided to give it a rest? That's fine, whatever you think is best, dear. It will happen when you're all ready." I should admit that I'm probably a bit biased because I really lacked confidence with DD1, and listened to my mother's (well intentioned and politely expressed but a bit overbearing) advice too much. My fault entirely, of course, but it did make DD1's babyhood more difficult than it should have been. With DD2 I was more confident, listened to the advice politely, but only followed that which I felt might work for us. Possible due to my experience I still think Knitterly would be best off just not feeding her mother any information. Perhaps it is too early for proper training, but it's unlikely to hurt so there's no need for her mother to comment. Especially since it's a pattern.
I would never use punishments or shame for a load of reasons. I mean, if LK was 4 or 5 and still pottying in her diaper (during the day, anyway - Mr K and I were both 8 yr old bedwetters, so I won't ever punish bedwetting), I might discipline by taking away a favourite toy or not allowing TV or something. But right now, my general attitude is "If you want to do this and can succeed, yay! If not, you're only 1, so it's not a big deal." She still gets pretty upset on her own when she doesn't make it to the potty in time. She likes being clean and dry and loves the claps and praise she gets for pottying on her little chair.
I have to agree with people above and the advice that was repeated many times in other thread. Please, please, please stop sharing your milestones with your mom. You are trying too hard to prove your mom wrong with LK's brilliance.
I don't why your mom is such a cloud of downerism, but she really, really is and that is really unfair. (My very average kid has 4 grandmas who all inform me of her amazing skills and intelligence cause that's what grandmas do. My husband and I also tell each other stories of her incredible perception and ability but I don't tell anyone else-even the grandmas. It's our secret until she wins the Nobel Prize, an Oscar and cures both cancer and the middle east crisis)
I know you didn't bring it up with your mom. But you still responded. You accepted it as a topic of discussion and made it such that she could voice her opinion. WHY WOULD YOU DO THAT? You know what her opinion will be and it won't be nice. Don't give her that power. Don't open that can of worms. Just smile, nod and move one. Once LK is toilet trained you can mention it, but bringing up any attempts to toilet train or talking or walking or writing or anything is just inviting misery into your life.
I'm really, really sorry your mom is like this. It sucks. It isn't fair. But that is the mom you get and you need to protect LK from this.
You are right.
I can share milestones with my mother in law, as she is every bit as thrilled as we are. Also, we would need to share the potty milestone with her anyway, as she watches LK often and I need her to know the potty signs and schedule (the schedule is new in the last 2 days, as it has cut out daily diapers to 1/3 of what they were).
Unfortunately, no matter what, my own mother would find out eventually about the early potty learning. I mean, she'll know by Christmas for sure, since we'll be there all day and I'm not going to make LK sit in a diaper all day if she doesn't want to just to avoid judgemental comments.