Older man meets homeless teen in.. . A mall parking garage maybe? Turns out she's pregnant, he takes her in and gives her a home until the baby comes (and of course they fall in love and L.H.E.A.)
Another one, very similar but I only read the beginning. He finds her in his backyard in a rainstorm. He thought she was vandalizing his garden but it turns out she was foraging for food(?)
Thanks in advance...