As long as you protect her from the sun, I really don't think you need to be concerned. She will probably love being in the water.
When my youngest was a baby, he was in the pool because big brother was in the pool. I used as little sunscreen as I could (because it's not recommended before 6 months) and put him in loose, white cotton clothing. I'm pretty sure I found some long sleeve onesies (probably made by Gerber) and some pants and put those on over his swim diaper. I also placed his carseat very close to the pool. When he fell asleep, I just placed him in his carseat, lowered the shade, made sure he was a safe distance from the pool and played with big brother.
I wouldn't worry about letting baby play in the water.