Hey dude I'm still here, waiting for act 3, so far my prediction is accurate-ish so here's what I have now:
3-4 months
Why? well, its been a bit over 5 months for the rest of the WRITING, so the last route will take about a month at worst (HOPEFULLY) and then the evil coding spirits might intervene and force a delay for at least half a month for the coding which would already take about a month and then there's the art... oh boy the art... yeah uhhh I'll just hope that you can take under 2 months on it alone.
I recommend you to be careful though, you are doing a LOT of stuff right now, especially with the added stress of college you have to juggle with the making of the game, so PLEASE take a break if you need one, we can wait.