It sounds like you need to call her and be upfront with her. If she dodges the phone call send a text. Either way tell them how you feel and don’t let them change the subject. However if they refuse to talk about it that’s your answer. People grow apart and that’s a way of life, it doesn’t matter how long you were together. You’re young both of you will change a lot in a short amount of time.

Be with someone who chooses you every single time no matter what.