Setting a date etiquette

Not at all. You have to do what works best for you and your FH. Find a venue and secure your date and then let your friends and family know about it.

Nope, you wouldn’t be wrong. There is no rule that says whoever gets engaged first has to be married first. However, since she has vocalized that she would like to get married next summer, out of courtesy and “keeping the peace” I would reach out to her and ask if they have set a date yet, as you are also contemplating getting married next summer. You never know, they may have already set a date and just not announced it yet; and you definitely don’t want to schedule yours on the same day!

Not at all. First come first serve. If she was worried about picking a date, she would have done so already. Go ahead and move forward with your plans!

She may have already set a date, so I would ask her first.

You wouldn't be in the wrong at all. Just to make sure there isn't a conflict, I would maybe reach out to your cousin first to let her know what date you're choosing (and if she already chose her date and didn't announce it yet, this would be a good time for her to let you know her date), but otherwise, go ahead and lock in your date!

Pick whatever day works best for you and they can work around that. The only thing you need to do is make sure the date is feasible for your most important guests. For some, that’s parents, for someone else that is a best friend. You get one day to celebrate and they get one day so they should be able to make it work Get in touch and see if they have picked a date and not announced it yet just to be safe.

I would let her know as a heads up because she could still be very well much trying to get things going. So, she may or may not have a date set yet. But by talking it out you guys can avoid having the same date.

No, you wouldn’t be in the wrong. Set your date for when it works for you. As long as the weddings aren’t on the same weekend, it’s fine