If you had that exact same player as an 18 year old, you'd have gem. Considering he is 19 you have lost a whole season of training.
But fear not!!
Considering he is that year older many managers will overlook such a player and your chances of getting m with your number 1 pick have increased.
Also, what position and height is this draftee? For instance a 6'0" PG will train faster in the top 6 stats than a 6'5 PG
And the same with Centres but vice versa. A 7'3" C will train faster in the bottom stats (IS,ID,SB&REB) than a 6,8" Centre
Good luck, I hope for your sake you manage to draft a gem, just keep in mind, whilst there are benefits to drafting 19 year olds, you will miss out on their most efficient year of training.