Hello All

I'm new to FFXIV. I'm a summoner, level 52. Up to now, I was happily enjoying the levelling up, progressing the main quest, the company stuff, doing side quests... Fun all along!
Yesterday, there was a brutal change: I had to confront Lahabrea. Honestly, what for a shock! It was for me like the level of difficulty has jumped straight from 50 to 100.
Even taking care to stay out of AOE markers, I was dying in no time.

Clearly, I'm not correctly prepared for that, therefore my questions:
- Do I have to wait having a level higher than 52?
- Is there a minimum level required for equipment (gear, weapons, accessories..)? Some of my gear pieces are only level 48.
- Is there any quest/dungeon or else I can do that would prepare me for the fight against Lahabrea? Something that would help reducing the gap in term of difficulty?

Thank in advance for help.