hey !
the issue about bumping into your ex - could you not go to a country pub or somewhere out of town firstly
also it is so natural for everyone to get so nervous on dates , but you do have a good start with the emails etc , you will be fine , talk about music , his work , your child , favourite films and it should all flow naturally, you have just got out of the habit thats all
u will be fine , enjoy it take it as it comes - if it don't work out its refreshed your senses on what its like to be in the dating game
its an experience !! enjoy and good luck !!!xx