Moms - when did your tweens become interested in the opposite sex?

My DS turned 10 in May and I am sort of amused that he has a girlfriend. He says they started "dating" last year. Dating consisted of the odd shared lunch box and him buying her a colddrink at the Valentine's Day disco. She went home with his cap that night. The friendship seems to fizzle off and then they apparently "broke up".

Recently he started talking about her a lot again. They have been chatting non stop on WeChat and he has become very shy about letting me have access to his tablet.

Honestly, it seems a bit young to me, but it all seems quite innocent, thankfully. I am not sure whats normal and what's not. I would love any thoughts!