Look, if you get into the West Coast university, don’t sell yourself short to attend a school nearby… for what exactly?
It’s highly unusual for college students’ families to visit them on campus (often, they come once when they move in, and once when they leave, and they certainly don’t casually “visit”). She wants to keep seeing you and she doesn’t want to imagine you far away. Same thing with “what if you need help” which is the same as “what if you need me?” and of course “what if you NO LONGER need me?” - what if you leave and never come back, what if you stop loving her, etc.
Ultimately, you are responsible to yourself and your future, to take advantage of that terrific opportunity IF it is presented to you. (Keep in mind that you could be denied ofr WL or get an insufficient package*…) Your grandmother is sad that you’re leaving and is trying to manipulate you into staying (even though she probably knows it’s not right… or she could have convinced herself that she knows better and you shouldn’t go far away.) You have to tell her you’ll love her no matter what, that you’ll be far but you’ll keep in touch and will come home for holidays, that you’ll miss her, but ultimately it’s time for you to start becoming independent and grow into the best adult you can be. Teach her how to skype, practice together, practice even before you leave.
If you’re admitted, as posters above said, talk to her with a trusted adult by your side. Don’t leave that to the last minute - you need to think about who’d be good, then ask them.
- although you can appeal...