@Venge, hi. Welcome to the forum. A couple of quick points:
First, when you create a new thread, try to put some indication of its subject in the title. A thread like this, for instance, might have "Order of quests" as its title, just so you'll draw people to it. Many people skip threads that don't interest 'em.
Second, when you post a thread like this that discusses details of the game which other people, playing it for the first time, might well want to not know about, please put "SPOILER" in your title. I'll do it for you on this one. We've had tons of complaints about spoilers in most of the game-related forums; so much so, that the site owner even put a sticky thread (which you should have read

) at the top of this forum.
As for your request:
SPOILERS FOLLOW...
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The only quests I would recommend against for a youngish party are Windspear Hills, Trademeet and the Planar Sphere. Even those aren't a problem if you're familiar with 2E rules, and playing on normal difficulty. Easiest quest at the beginning is in the circus tent, right in the area where you emerge from the Irenicus' underground funhouse.

Second easiest and the most rewarding, is Nalia's stronghold. You'll come away with a lot of fine enchanted ammunition, and a great enchanted melee weapon. You meet Nalia in the Copper Coronet, over in the Slums. (Personally, I've never cared to add her to my party, but that's a matter of personal taste. There are no "good" or "bad" choices in forming parties.)