Don’t worry about it. I’m pretty sure you’re going to meet a whole load of other males in your life. Like most heterosexual people, you’re simply not going to find every single person you meet attractive in
that way! And even if you do, chances are, since the incidence of homosexual inclination in the population is probably no more than 5% at best, you’ll be unlikely to be rooming with someone who’s going to a: be similarly inclined, and b: even if so, is necessarily going to find you attractive anyway.
You are, wisely, going to practise modesty in private situations (I’d recommend that to anyone, so you’re on a roll here already).
The Church recognises the trials that having homosexual inclinations can pose - it is, after all, a rare occurence in the grand scheme of things (which is why it’s called ‘objectively disordered’ - not as a put down, but simply the ‘natural order’ is that the human race is heterosexual and that’s what you’d almost certainly expect upon meeting any random person)… The Church understands that you’ll be less likely to be able to marry and have the blessings of marriage and children and understands that this is a cause for sadness for you and everyone else who cares about you. Like all people who are unmarried, the chaste life (i.e. not being sexual with people) is what you’re called to live. And you’ve already accepted that… so look, you’re on a roll again
There’s nothing to suggest you should limit your normal interactions with people of the same gender. How would you exist in the world if you did? You can hardly go and live in a cave, can you?
Simply cultivate ‘disinterested friendships’ - by which the Church means friendships based on mutual interest and support and leaving out the physical bits that men and women would do. I get the feeling you’re in your teens, so doing this will certainly show you as healthily mature for your age. It’ll get you credit in many areas and people will probably see you as the “go to guy” when they’re having problems. And nothing is so affirming as people seeking your counsel.
Enjoy your trips. I’ve been to Paris. I can tell you it’s wonderful. Barcelona is great too, so I’ve heard. I’ll bet, no matter who you room with, you’ll be so overwhelmed with all those new things you’ll see, any other issues won’t occur to you.
Have fun and stop worrying. You’ll do fine.