4 years at GT. He can be a GREAT college player. He's already very good. A lock for All-ACC Freshman team - but won't be Rookie of the Year (Dennis Smith will get that).
For comparison -
Dennis Smith at NC State - he's the best freshman (talent wise) in the league and almost a sure one and done ... when you watch the two you see more offensive skills in Smith, Smith can create his own shot, etc ... Okogie plays within framework of team and with a lot of energy. If Okogie were on another ACC team - one with more depth - he likely would not be putting up the numbers he is here
I would he shocked if he even considers leaving early - best comparision is he's another MGH like player - better shooter from perimieter .. with higher up side. His skills don't translate as well to the NBA as Shumpert, Bacon, etc. He'd be a 2-guard in the NBA.