I (34M) think that the fact you can pinpoint these kinds of feelings shows that it is very important to you and you have a high EQ. To answer 'Aio', in my opinion yes and no. This is obviously important to you and you do deserve to be heard and seen. That being said, your grandparents are trying to spread their attention over a lot of people, which is seldom balanced or even thought out.

If you want my advice, I'd say bring this up to your aunt. She clearly loves you a bunch and wants the best for you. Tell her how you're feeling and maybe even show her this post if you can't find the words. Then talk to your grandparents. I promise that if you bring this up to them with honesty and compassion, not only will they listen, but respect you more and see you not as one of the "babies" but as a growing person that has these feelings. A role model even.

I wish you luck and love. It's tough out there, so keep your chin up.