I'm a rather anxious person by nature, but when it comes to play time for DD, we let her guide us. we are never too far away "just in case" but i don't want her to have my anxiety issues, so i force myself to suck it up, and i let her guide us. she's the kid that climbs to the highest slide in the playground (at similar age to your DD), goes on the trampoline etc - but she also doesn't have a lot of time with other kids between her age (2 now) and her cousins (7-11yo's) so boisterous 3-4 year olds can be a little overwhelming for her. we went to the next door neighbors for their sons birthday - they had a jumping castle (the huge inflatable ones with obstacles inside, slide etc) - it was too much for her with all the other kids in there so she asked to come out and just play on the trampoline where it was calmer

your DD will let you know by herself if it's too much for her

now, ZF - you know my DD will be following yours at the play centre next week - hope they don't lead her TOOOOOOOOOOOOOO astray lol