Is it normal to wear my sister's clothes when shes not around?

I always wondered what it would be like. To slip on some of my sister's clothes, I jerked off about the fantasy for weeks. Then, the night came, i was 14. my sister was at a party, my dad and mum were in a hotel, so i was on my own. I went to her room, put on her best lingerie, and had the best jerk off ever. I do it any chance i get now... but i always think... IIN? or am i a creep?