When Rebecca meets adult Tommy again and they begin kissing, she said it feels weird....
I thought they were just close friends, he seemed more interested in pursuing a relationship then she did. I never actually saw them hold hands either.
And was she really a virgin until she slept with the clone?
If she hadn't felt weird things might have moved along a little faster and they may have had sex so we wouldn't have had the dramatic loss of virginity after all that time. Even though she was somewhat eccentric even as a child she was still a virgin who had been waiting to see her fantasy childhood love for 12 years. She probably wanted the moment to be a little more drawn out.
On the other hand, if they had had sex who knows what butterfly effect would have happened. They may never have gone on the trip together or maybe he would have thought to look before getting out of his car... and no movie about cloning.