How can i get my 3 yr old daughter to let me hold her in a pool?

my daughter used to love to go into the water with me, lakes, streams, creeks, pools, whatever.. She wouldnt be scared so jong as i held on to her. but now she is getting older and i wanted to try and show her a little bit of swimming, maybe how to kick her legs in the water or something. The problem is now if i try to hold her or come near her, she starts to panick, freaks out and throws a fit (in the kiddie pool, and i havent even been able to try holding her yet). if shes by herself she is fine, shes never had any tramatic experiences and i just dont know why she is doing this all of a sudden. does any one have any ideas as to how i might be able to overcome this fear she has developed for some odd reason??