I am 18 and have been in a relationship with my girlfriend for 3.5 years. She is 23, but the age difference never seemed to be a factor in our relationship
18 - 3.5 = 14.5
23 - 3.5 = 19
15 / 20 16 /21 17/22
5 years at such a pivotal growth time in YOUR life IS a big deal. you are just getting out of high school and should not be burdened with a drunk older g/f who is making a mess of HER life. and while i am sure you are a VERY nice mature young man with a good head on your shoulders, 20 year olds shouldn't be dating/involved with FIFTEEN year olds.
get your head clear and get ready to take on the new adventure of college. learn, explore and watch the partying!