Personally i don't see why you would want to, the Go boards are great boards even for more advanced sailors who want a sweet freeride in good conditions. I know some might dissagree with me but the Go139 in my experience never lets u down once it gets planning in a steady wind and it leaves u the time to adjust when wind falls. The only trick is when you get overpowered to get your tail under controle, but thats easily solved with other fins.
You can also check out the Carves. I think they're deep TT aswell so thats a +, they're narrower then the Go boards so the'll plane a bit less fast but they'll have more controle in strong winds. But i think, if you're really learning everything, the Go139 is your better choise and i don't think you'll regret it in the end.
Once you get the Go139 fully under controle and know like most trechniques and start looking for a 85 L board or something you can still keep the Go for lighter wind days as your sailrange is ideal for it and your smaller board for the rest