Ask yourself that if the girls has told you all what she told you after few months of your friendship,will you have still moved ahead with her?
I feel you are infatuated towards her . it is just 8 months of relationship rather total time knowing each other.
I feel the same for her that even she is not clear of her priorities or might has not made any till date as she is just in college.Getting married might be a decision at your age but not hers. The way she is reacting to your decision of moving on might be because she has to come out of her comfort zone ( with you) and loose a settled guy…I might be wrong!
I feel you should give more time to your relationship . Generally long distance relationship are easy to end when not bonded with true love. You will have your answers.Either you have to accept her with her past ( as you say you love her) or move on and don’t care about your anxiety.Choice is your’s.
If her being involved in multiple relationships is not acceptable to you now , it is likely to be the same in future. This will not bring happiness to any of you…
Thats just my views.