new player, trying to decide on class

[Niwashi]

That is why I tend to try to find the jack of all trades class. The one that can do a bit of everything so I can help with all roles.

Well, this game doesn't exactly have any jack of all trades classes. They're all specific to a single role, either tank, healer, or dps. Instead of giving classes themselves the ability to adapt to being used for multiple roles, the game instead gives our characters the ability to learn multiple classes. You can help with all the roles if you level one or more classes from each of them.

(If you've done your level 10 class quest at the ACN guild, you can go to other class guilds and do a quick quest at each to unlock access to those classes as well. The marauder and rogue guilds are there in Limsa Lominsa, as are the Blacksmith, Armorer, Culinarian, and Fisherman classes if you want to branch out into crafting and gathering as well. The rest will have to wait until you reach the level 15 quest that opens up access to the other main cities. And then there are extra jobs added in the expansions that don't unlock until you reach level 50.)

Many players level all of them. Once you reach endgame, you'd have a hard time earning enough gear to equip all of them equally, so by that point you're best off picking a favorite to focus most of your attention on. There's really no need to choose a favorite or "main" class until then (though many people do). And even once you pick a main to focus on, you can still change it any time you want. So don't worry about what's going to be "best" at some point down the road. Try them all out, and continue playing whichever ones you enjoy.