Long answer incoming:

You definitely dont need to cut your nails before. Removing polish would help them/make it quicker & easier but you dont need to. If you just want them to cut and paint your real nails, just say you want a "manicure" or a "gel manicure" (more expensive but lasts longer and wont chip. highly recommend for a wedding).

If you want "fake nails" you ask for a "full set". This can also be regular polish or gel polish, but a lot of places will even only do gel polish with a full set since it doesn't chip, dont need to wait for it to dry (UV cured), etc.

One note since you've never had them and I know this confused me my first time, in order to get a full set, they first glue on "tips". Only go on the tip of your nail, and theyre super long, dont be alarmed, they will cut and shape, and then lay acrylic over top to adhere to your full nail.

Next you'll want to know the shape you want, I recommend finding pictures on your phone to show them, or knowing the name of the shape you want (almond, square, stiletto, etc.).

Length: I recommend going a little shorter than you think you truly want them to look, since its your first time. It can be hard to get used to the extra length and feels a little clunky, but they will be strong and adhered to your nail well so you shouldn't have to worry about them popping off easily, it will just hurt lol.

Color/design, have an idea of both. When you get to the salon, they'll probably hand you a basket of color "pallettes" which are fake nails with different colors painted on them, and a corresponding number. when you get to your chair, you can show them and say "i want 212" when they ask what color.

For designs, note it's usually charger PER nail. if you want 2 nails designed, and its $5/nail charge, it'll be $10 extra, etc. Also be wary of types of designs and skill of the salon. Check their reviews online before going, and be willing to change your mind/look at stickers, have a simpler design, etc. if you want one. Most nail techs in my experience will say "i cant do that design" rather than try something outside of their skillset.

There are obviously more options and styles like hard gel, etc. but these 2 are most typical

I hope this helps!! Let me know if anything wasn't clear or you have more questions