you don't have to "make the move" up and never play $3.40's again

I'd say just try a couple $6.50's and see how they go. You're not going to magically lose $100 unless you never make it in the money 15 consecutive times. The $6.50's aren't really hard. The only difference I'd say from the $3.40's there is is that there's a few better players, of course, but mainly people are generally better at playing tight in the early stages. A lot of people still have trouble adjusting to shorthand play though, and you see some real monkeys when it gets heads up sometimes still.