I might want to quit the swim team? Basically this means I have way more time to have fun but there won't be four girls my age for the relay at city championships.
Is there a reason you want to quit besides having more fun?
My relay is so slow, I think I should spend my time doing other things.
If you enjoy swimming you shouldn't quit because you are slow. Practice will improve your speed and maybe you can win the competition.
I don't have time to improve my swim speed I have way more fun things to do.
That's up to you to do what's most fun and enjoyable, but don't you think quitting because others are better is a wrong reason to quit? Why don't you try giving it another chance, but instead just not being as intense as before?