The gear you're running now will likely be the easiest to start off with and skid with, but not to go fast - there's a compromise you'll have to make.

I'd go ahead and do as said above and swap your chainring to a 42, or a 44/46 kind of range, that way you leave yourself open to a nice range of ratios by only needing to change the back cog in the future.

I run 46:15 on 23c tyres with 170 cranks and it's a pretty tall gear (80GI?), I started with a 17 on the back which was nice - I was riding 52:19 on my roadbike for a long time, which was around the same range. Use the gear calculators and figure out what you want to run, I guess. I'd go with 60-65GI, or if you're feeling adventurous 65-70GI to start off with, ride it for a bit while you get comfortable with the resistance/skid/skipping on that gear, and then see how you feel.