I was with some friends at a convention this weekend, and I presented as male. Even passed in front of my mom and dad (my mom was the only one that complained, of course). Anyways, I felt so awkward going into the womens' restroom because I felt like I passed 80% of the time, but since I was with friends and my parents I could not use the mens'. Even if I was alone, I would have felt self-conscious going into the mens' room because I don't have a STP and have never really had a desire to have one. (Bathroom business is like sex to me: the way you do it just depends on the tools you have, and that doesn't have anything to do with what I feel inside.) But it definitely felt worse going into the womens' room, I felt like eyes were on me a lot, thinking if I was a confused guy going to the wrong place. How would you deal with this? Since I am not 18 yet I still go a lot of places with my parents and I can't really avoid that rght now.
Hmm... At 17, I would have tried putting a little distance between me and my parents. Hung out with my friends, and when nature called, used the mens room. Though with being out to your parents, and presenting as a guy, I would have just walked into the mens room anyway. There are stalls in there, and some guys do use them....
I was going to suggest the same thing, but confuzzled82 summed it up perfectly. If they are uncomfortable with you using the male restroom, you could try talking to them, or just saying something along the lines of "I don't want to make anyone feel uncomfortable because there's a boy in the women's toilets." Maybe if you needed to use the restroom, you could go on your own, and ask them to meet you in one of the shops or outside somewhere, so they wouldn't see which toilet you used.
Lots of guys use the stalls for different reasons, and I can guarantee that most men wouldn't even blink an eye if a cis woman walked out of a stall and the bathroom. They might be a bit puzzled, but she wouldn't be ridiculed for it. Especially if it happens somewhere with crowded bathrooms like a bar or big event! I think women are more sensitive about bathroom space. I'd say just use whatever is more comfortable to you, but I think you'll find the men's room less judgmental to begin with. After all -- there's not exactly a lot of eye contact. It's more of a 'stare at the wall and get out' kind of ordeal Hope I helped at least a bit
I'm pretty sure that if I made any reference to being trans or being a boy, my mom would dismiss it immediately and say, "But you're a girl," and act as if my coming out to her had not happened. Astral: that's very interesting, I've never been in a restroom with guys so I had no idea about the judgemental thing. That actually kind of reassures me a bit, thank you. xD
Tai - don't give her the opportunity. You only get one life. I'll quote the marketing department of a certain truck company... "Grab life by the horns." On a side note, that needs to be added to my signature....
With what you said about coming out to her, try telling her, and if she dismisses it, repeat yourself. Make her understand.