It's great to be able to do things like this with your family. I started aikido 3 years ago, after my 2 sons (now 11 and 13) had been in it for a year (we also had no prior m.a. experience). I loved it from the moment I stepped on the mat, and my kids taught me how to do front and back rolls.
My youngest then joined in at age 5 and I help out with the kids class every week (although my instructor usually steers me away from working with my own kids
It has been really great, and, although there have been a couple of moments when they've thought about quitting, they've ended up continuing with it; my oldest has even said he would like to continue into the adult class when he turns 14 next year.
Glad your enjoying it.