So I'm about to start the thieves guild quests to obtain nightingale armor wich reach max lvl at 32, but I don't want the bow yet since it's maxed out at lvl 46 or something. is it possible to do that? which one do you get first?

Wish I'd waited for the bow. But...even now since I can't double enchant items, but can upgrade with smithing, it's doing more damage than any other bow I've come across, including a daedric bow I enchanted with fire. Still... would have been nice.

Also wish I'd waited on the Nightingale Blade since it's leveled too. Though if you wait too long on it, apparently the highest version can't be sharpened.

When the creation kit gets released, maybe someone will make a quest award leveler... or if we're really lucky, one that's immersive, such as having them improved by Karliah.

Comfirmed as true.

The bow, on the other hand, is the best bow around in my personal opinion.

so can you take a break between the quests and wait til the bow level up, after getting the armor or are the quests intervened somehow?

you can wait... you get nightingale bow like 2 quests later...

With the level bow I have, its base (or upgraded on the wheel) damage is easily surpassed, but factoring in the enchantments, I've yet to see its equal. It also has a decent number of charges. My favorite bow I've found so far.