This is by no means telling you you're too young to say never, I'm 30 and I wonder if I'm too young to say forever
But my best friend, who was 33, got her grandmothers rings when she was engaged. Long story short the wedding never came around, with good reason. But she kept the rings, and wore them, for years. In doing so they lost all the meaning her grandmother had intended for her in that gift. Rather than them being a symbol, to uphold the same promise for her, that they had upheld for her grandparents life time of love, they became a symbol for the memory of her grandmothers loss.
They still meant a great deal to her, but they did not mean to her what her grandmother had wished, nor did they seem to suit the purpose any more once she did meet someone she did marry.
Jesse, maybe it's the romantic in me but I think I would kind of like that little vow of confidence hanging out there in the universe, that if the day ever came, I'd have that piece of history to commemorate it, to continue the commitment it was made to uphold.
In the mean time a conversation with mom, telling her their importance, and asking that they not be sold if you never get around to marrying, should still find them in your possession one day.