Don't worry about feeling like a sand bagger by doing the beginner crit. They are very hard even if they are short. Unlike velogirl they aren't my favorite so I may be showing bias-- the last one I did was part of a stage race, 45 min (mixed cat 4-1 ack) and I would have given anything to just get pulled already. I thought the 101 mile road race the next day was easier.....
Even if you are comfortable with longer distances, crits are generally max effort for just about the whole thing so they are usually anything but easy no matter what it sounds like. Plus you have to be on your toes about your cornering and watching out for other people.

a little OT - velogirl have you ever come up to Oregon for any of the stage races there? There were lots of CA gals at Elkhorn this year. (I did several OR races this year and they were a lot of fun and very well organized)