Can girls swim topless with boys

Why do some girls go to the swimming pool topless?

Hey guys,

to begin with I am a ’boy’, am 13 years old and identify myself as a gender fluid.

I'm currently single but have a best friend (not a best friend .. the male friends category is pretty empty for me).

For a long time I have been thinking about whether I should / may / can ask her, whether we can somehow swap swimwear when we go to the swimming pool (at the moment I go to the pool in a bikini rather than swimming trunks).

The last time we were in the swimming pool I asked the question for fun and I also told her that I wasn't serious at the moment.

But I don't want to look like an idiot to her either. (Going into a public swimming pool in a bikini is no problem for me).

I also had the idea that she and I would go into town together and each other to choose a bikini and the other to put it on too

However, it would only be possible if the size fits ... but when I grew up as a boy I had little idea about the subject and, for example, I cannot estimate the size of the top Information is .. Estimating the lower part will not be a problem, I think, but at the top we are difficult.

can you give me tips on how to assess the top or how best to ask about the size without looking perverse or intrusive?

and what do you think of the idea that you and I can choose a bikini for each other and that we have to wear it .. regardless of whether I am male that day or we like it to look like?

And most importantly, how can I convince my conservative parents that I can do that.