Your definately already capable doing 12's. Just from your 109mph is easily 12.90's or even 12.80's. Those high mph are from the tire spin. You'll probably see you 12's with 105 mph.

Are you driving around the water to do your burnout? With streets you don't want to wet your tires. Also when you drive around the water back up to get enough space for a nice burnout without crossing the staging beams. Just don't back into the water. If driving through, make sure your fronts aren't picking up water then dropping onto the rears when you launch.