What was your level when you did it?

I am at level 17 and I can't manage to do it.
What I find surprising is that in earlier sections of the game, when faced with an insurmountable challenge, it was fairly easy to find side quests and level up before coming back to overpower opponents that previously caused you problems.
Here, it seems that I have done pretty much all there was to do on Sentinel Island, except the quest involving the old ghost looking for the whale.

And despite that, the path to the Bandits's barracks is a narrow corridor with a bunch of guys at level 16/17 who have the ability to heal themselves, which is clearly too much for me.
On top of that, the bandits' boss is at level 16, but seems much more resistant than other opponents of the same level.

Thanks.