Should i keep waiting for her?

Ok so i am 15 and have been waiting for this girl for 3 months while she has been dating this other guy so me having to wait has made me want to give up. but at the same time just about 3 days ago we kissed and cuddled while i stayed the night at her house just before that all happened i asked if she still liked me and she said yes and i said ive been waiting for a long 3 months and i am on the edge of giving up but her reply was no please don't give up i still like you. She also says she loves the idea of being with me and when we are with echother we both feel like were like living a dream when shes not with me she gets frustrated and upset easy so do i when were with echother we are both always happy and another thing we stayed up till 4 in the morning the night before her quince talking about being together with echother and how it would be and how she wants to be with me but for some reason she cant leave her boyfriend even after all of this has happened she also had a hard time deciding between me and him at the beginning of all this as they were about 3 weeks into there relationship. So should i keep waiting? Or Should i move on? i really like her and want her i am almost in love with her please help ive been wondering for months what i should do thank you.