What could cause throwing up often in my 6-month-old daughter?

Hello doctor,

My daughter is 6 months old. She is still drinking formula milk (four to five bottles of 120 to 180 ml per day), but I have been giving her a little bit of our food for the last few days. So today, I gave her water for the first time (5 oz). She drank the whole cup of water, and about one and a half hours later, she threw up quite a bit, mostly water with a bit of mandarin in it (she had mandarins, taco, and beef for supper). She also had a bath a few hours before, and she accidentally swallowed some water, she gagged, and a lot of water came out of her mouth, so I figured it was fine. Now I wonder if the throwing up was from drinking too much water or too fast or from the bath. She is acting normal, aside from throwing up. I would like to know if she is fine.

Thank you.