Is it normal i like my sister

It all started when I was 13 , I picked up my sisters thong , (she was 14) and i sniffed it and loved the smell of it and jacked off that night with them and came all over it and put it back in her draw , never heard anythng about it.

One night when I was 14 and she was 15 she came home drunk and she was in deeep sleep i felt really horny and went down to her bedroom to get some underwear and she was sleeping with nothing but her panties on so i went to go touch her tits ; no reaction , unzipped my trousers and put my dick on her lips ; felt sooooo good so i start sucking her boobs and move down to her panties , licked her camel toe and stuck my dick where her vagina would be and started rubbing up and down till she woke up , we had sex that night and everynight after that for 2 and a half years , so is this normal? i am now 20.