I'm a NIT who wants to be more aggressive.

[Dire]

IMO, only do it if you're doing it because you want to have more fun while playing or to prepare for moving up to higher stakes games. Your win rate will almost definitely go down at first and stay lower for quite some time, and your variance will also likely rise significantly. It takes alot of experience and time to start figuring out what people are willing to call down with, what they'll fold, when your second/third pair can be value bet on the river, etc..

Its generally much easier to hand read in situations as a nit since you're rarely in a marginal spots, and you're often just WA/WB. And people don't just completely freak out and do crazy things against you too often. Play a bit looser and you enter the twilight zone.