Sun and baby

In a few weeks my little brother is coming to visit, he is 15 and we plan on going to fun mountain witch is an outdoor water park with a whole bunch of water slides my tiny lover just turned a month, I know she can't wear sun screen yet is it fine if she stays in her car seat in shade ? I breast feed so can't really leave her with bfs mom I can pump but then I'll be missing bb should I just stay home or is there a way around this