sexual intercourse failed/ virgin

so, me and my girlfriend tried to perform sexual intercourse...approx. five times already, i'm not too embarrassed about the size of my penis, not too big...but perhaps it can be for her? she is a small lady, who is a virgin, had her hymen broke when she was a kid, and i believe she hasn't masturbated before. When it hits the entrance, it just couldn't find it way in even when she was on top of me, missionary failed also.
She is turned on for sure, since it was extremely damp down below, lube was used...yet again, another failure. I don't think she was that anxious...so WHY on earth wouldn't it go in...well it hurts her when i go hard and tries to penetrate...so i hesitate a bit, i don't want to hurt her...like my penis hasn't even explored inside her YET! maybe some girls has slightly tighter.... ? and then i sort of lose interest for a moment and had to give it a rest after hulk mode, and continued a bit after that... i can see clearly she's embarrassed about it thinking it was her faults, while me soothing her with words, stupid condom! =[
What should i do...