Yesterday, I ran into an old friend at the supermarket. I was shocked to see him in town
because I thought he'd settled down in the States. He started telling me about his life,
things that were new to me since we hadn't talked to each other in years. I couldn't believe
he is married and has a one year old baby. After an hour of catching up, we left. We forgot to exchange
our phone numbers. I hope we'll run into each other again soon.

Are there any mistakes?

No mistakes!
( I would have said ... couldn't believe he was married and had a one-year-old child.)

And I'd say We forgot to exchange our phone numbers.

Best wishes, Clive
Students: We have free audio pronunciation exercises.
Thanks CJ and Clive.
Teachers: We supply a list of EFL job vacancies