She's not technically my cousin?

I knew this girl about a year before her mom married my uncle back in 2005. We had a lil crush on each other, but did nothing about it. Now, i saw her for the first time in 2 years (we are both 16) and she asked me if i had a Gf. She made me sure to know she was single too. She wanted me to snuggle with her a lot. I still have feelings for her, and she for me. But since her mom married my uncle, its weird. advice? Is it still wrong since we knew each other before hand?