Still 22 games to go in the season, but I thought I'd post this for comparison sake. It's MB3's current season compared to DeMarcus Cousins rookie season in 2010/2011. Boogie turned 20 before his rookie season began whereas Marvin is and will be 19 for most of his.
MB3 -- GM: 46, MIN: 24.9, PPG: 14.0, RPG: 7.2, APG: 1.0, BPG: 1.0 FG%: .513, 3PT%: .267, FT%: .696, TO: 1.7
DMC -- GM: 81, MIN: 28.5, PPG: 14.1, RPG: 8.6, APG: 2.5, BPG: 0.8 FG%: .430, 3PT%: .167, FT%: .687, TO: 3.3
Very similar numbers. Except MB3 has done it in fewer minutes. MB3's shooting numbers are much better overall and he has half the turnovers.
While they are two different players, I think this comparison demonstrates that Marvin is well on course to becoming a pretty darn good player. It's likely many of his season ending numbers will be better than above, considering how he's performed in recent weeks.