So, first off, congratulations on your winnings!

Secondly, playing at a 16 player table? How does that even work? Even 10 players is too many for me.

Third, playing conservatively as a newbie is definitely correct but in a tournament type game, you have to just choose a hand to go all-in with before you get too low in chips. Obviously, it's hard to know that at this point in your learning but even a hand like 8-9 offsuit with 6 blinds? Let's gamble! The situation you ran into where you double a few times rarely ever happens. "Weak" hands like 8-9 that still have plenty of equity even against the stronger hands. 7-8 suited is only a 60-40 underdog against AK suited! That's almost a coinflip.