Guild Wars 2

Thanks guys for the heads up information really helped me.

Hi im a relativley new player started in November. I have a guardian that is lvl40, and I just reached the first dungeon in my story. My questions are:

After i finish my story dungeon would it be a good idea to start farming the exp part?

If not what is the best time/level to farm exp dungeons(not just AC)?

And what is the best type of gear to have to farm these dungeons at said time/level?

Thank you for your time!