I take it from the title its an Avistar...I have been flyin mine for about 2 years now and a trainer is definately a good idea. The avistar isnt like most trainers, its not gunna float as well as most, and it reacts a bit quicker than say a superstar...or some other trainer with a flat bottom wing and a lot of dehidral.
Get an instructor...you will be happy you did!

-Dustin