Does anyone have a problem with their daughter peeing too much to potty train?

We started introducing the potty at 18 months just to get her to know what it is. We have just been reminding her and showing her where to go and what to do. We put her in undies and let her run around and put her on the potty and she went pee for the first time. Then within the 10 minutes after she peed she peed 3 more times! The last being so much it soaked a towel. I know she drinks a lot and we try to keep it back a little. But I don’t understand how she can pee that frequently! I really want to know if anyone know when kids are PHYSICALLY able to hold it. You use their muscle to stop and go?