You can do it. I would put the 1/2 later into the season next year so that you can throw an olympic or two in there before it. It never hurts to have more experience.
I did my first sprint last September, and I'm shooting for the Timberman 70.3 in August of 09 (It's on my birthday!). There are still open slots!
http://www.timbermantri.com/timberman.html