Of course if you want an EB2, you need to start over. But you do get to keep the priority date of your original EB3 perm, so that should save you some time. As you can imagine, a LOT of EB3's have done the switch to EB2 to get GC. This was at a time when EB3 was ALWAYS the way to file as the quota was never exceeded. I was EB3 simply because it didn't matter back in 2001, and the company didn't want to bother re-filing for me when thebacklogg hit in 2004. So I waited.
But, I doubt if your position would be considered EB2, especially after what you just said about your pay scale.
In any event, you won't be filing I-485 for years, so you have plenty of time to come up with some creative options, including getting a Masters and switching sponsors.. Besides, Congress might just change the rules at some point, opening up EB3, and you would have that I-140 in your pocket.