Is it normal that i had anal sex at 13?

This is a treat some guys dont get in their lifetime. When i was thirteen, my next door neighbour and best friend (a girl) were having a sleep over, something we did at leastn once a week. We would always share the same bed. Anyways, while i was asleep she started to play with my penis and i woke up to her giggling as it got hard. After her doing this for about another minute she pulled down her shorts and underwear, turned around and i think you know what happens from here. We had sex until i came.We did it a couple of times afterwards and we're still friends but we never really talked about it in much detail. Is this normal? Please share your stories.