Fermenting too long?

I made my first attempt at a clone over 2 weeks ago and used this as my fermentables:
3.3lbs Briess wheat lme
3.3 light malt extract
I then steeped these grains
2.0 american 2 row pale
1.0 flaked oats

I used white labs yeast for the frist time and used american hefeweizen yeast. There are still pretty active fermentation ( bubbles out of air lock every 20-30secs.) 16 days later. I've made around 10 brewer's best kits before this and never had anything this actively fermenting ...just wondering if i should worry lol. Thanks!

You should take a gravity reading to determine if it is done. Same reading for a few consecutive days means yes. I use glass carboys and you can kind of tell visually when things settle, then take a reading. I usually ferment 3-4 weeks before taking my gravity reading. Sometimes if I wait long enough I take one reading and if its low enough, I just bottle. You should usually know the ballpark of what your final gravity should be. That is if you know your original gravity. Then you can calculate your alcohol by volume as well.

I OG was 1.058 and FG should be around 1.015. the smell thats coing out of the air lock today really stinks. earlier it just smelled hoppy, i hope its not contaminated.

Its probably not. Lots of strange smells come from fermenting beer. If you keep things sanitized and are a conscious person when it comes to cleanliness, it would be difficult to contaminate your beer. Do you you have a bucket or carboy? I would check the FG after three weeks. Then again a couple of days later. If it is the same, bottle up.

I tend to get strange off smells when fermenting wheat beers. I'm guessing it is characteristic of the strain of yeast. My wheats also tend to have more vigorous fermentations and almost surely cause the need for a blow off tube. In any case they always end up tasty!

Smells out of airlock means nothing, bubbles in airlock mean nothing. A hydrometer reading will tell you if your beers done.

Yeah. Ive blown caps off of carboys even with a blowoff tube! That one fermented a long time before things settled. If it is a bigger beer, it will take more time. Ive gone a month before bottling on most of my bigger beers. 2 weeks primary, 2 weeks secondary. I use secondary every time. Matter of preference. Most of the time, Ive gone through more than half of the batch before it is truly ready. My last batch is still getting better every week and Im at 6 weeks in the bottle. I will gain more patience as I stock up. I brewed two IPAs back to back so I could store 100+ good strong beers. Enjoy your brew!

By "bigger" I mean 1.060-1.080

Alrighty, thanks for the advice...guess i'm just nervous since its my first none "kit" recipe.

well i racked it to secondary last night F.G. was good and i threw in some hops as well.