Took me about 3 months to start sparring (at which point I still sucked but was in great shape), then took 6 months off. Then came back for 4 months, skills improved a lot but conditioning sucked. Had my fight (lost, but the guy went on to win the open class Gloves this year and earn a North American ranking so he might have been a pretty tough ask for my first fight), at that point I was beating up all the other subnovices and could hang with most of the novices up to around 6 fights. Could provide decent work for the lower-level open class guys. The next 5 months I got where I had to take it easy on most of the subnovices and lower-level novices. Conditioning was still lagging (I felt like I was a lot better than I could demonstrate in the gym. Then I stopped boxing.
I consider guys who are open class 'good,' and a few novices who dominate at that level too. I'd say after about a year of training I was 'getting there.' Thought I was alright for a guy as out of shape as I consistently was.