What public restroom should a newly out ftm use?

I'm 16 and came out as an ftm a couple months ago. I always p. No stranger has ever called me she or her. But I have never used the mens room. I once went to a water park and was approached by a worker asking if I was a girl. Whenever I use the women's room I get dirty looks. But I just don't know if I should change rooms. I'm afraid of the legalities if anyone finds out. I do use a stp and am very good at it. Also, I want to start using urinals but I only use a medicine spoon. So if there is no divider I will probably use a stall. I just don't know if I should change restrooms since I'm not fully out to everyone. What if I see someone that knows me in there? Please help.