Curious aunt

Okay so recently I have been partying a lot with one of my nieces this last time we went on vacation and we shared rooms I wasn't into anything but once I saw her shower/change I started getting curious about being with women I need advice from other women on how to make a move I don't want to make a move and be a weirdo I need to be sure she's into girls too how can I find out or where do I even start?