I hate that too when I'm shopping, but a view from the other side, I work PT in a women's store. What you described is what we are supposed to do. We see them bring pants in to try on, suggest tops, they have tops, do they need a bottom, or jacket, or jewelry, etc etc etc. Unfortunately, we, as the employees, are told if we fail to do all of what corporate dictates we do.
that being said, there are always some, both in my store, and other stores, who push it to the limit. Who won't take no for an answer. I myself am as low key as I can get away with. I will ask of they need any help, and if they say they're just browsling, i back off, but let them know if they do need anything, please let me know.
Although sometimes I am specifically instructed to seek out additional items and bring them into the customer. I hate that. My feeling is, if they WANT something to go with what they're trying on, they will either ask me, or look for it.
I encourage you to let corporate know. Store management won't help as they are the ones telling us to do that, but corporate sets the guidelines. Tell them how much you dislike that type of approach, since I can tell you, we can't do anyting about it, at store level, unless the associate is rude, which this doens't sound like she was.