It's a big risk spending bulk points considering at this stage you'll have between 2-4 active managers picking before you (that can now potentially access the information you've sent through to find these guys).
In general, I have no qualms with 19 yo. I got a beast myself last season and have found they can easily exceed a decent 18 yo overall, obviously depending on skill distribution.
Naturally, I'd go for the 19 yo in this situation for a few reasons:
1. A+ vs A
2. Stamina will be better from the outset based on minutes played
3. FT are also a pretty strong indicator and this would be a bonus based on these stats
4. As you mentioned, a 7 foot PG could be great news from a training standpoint.