I need advice on a 3 month old going to a pool? Before you judge me... My daughter birthday(she will…

I need advice on a 3 month old going to a pool? Before you judge me... My daughter birthday(she will be 4) is coming up on Monday and she REALLY wants to go swimming and my husband is FINALLY OFF for the week and I want to do something for her with all of us! My baby boy is breastfed.. is there anything I should know that can be helpful? I know the common sense things like shade and sunblock and a rash guard and hat for the baby... but anything else in particular?