I have the Avistar with an os40 and have no problem taking off in the grass. Even when it is a little tall the only problem comes when cleaning the chopped up grass from the underside.

I'm also new to the hobby and if you haven't tried a simulator yet I would recommend trying one. I used Realflight daily for a month and landed 3 times solo on my first day of flying. It is also alot of fun when it's raining out.