Unfermentables?

[PurdyGood]

I brewed my 1st AG batch (BM's Cream of Three Crops Cream Ale) according to the recipe. It has been in primary for 16 days, and I was really hoping to bottle today to free up the primary for another batch; I don't have another weekend off of work for 2 weeks.
So I checked the FG yesterday, and it was 1.020. OG was 1.042.
I stirred the sediment up and placed it in a warmer area, and have not seen any more airock activity in >24 hours. Will check another FG in a few hours.
I had some issues with the mash-in temp because my thermometer was acting up; I originally mashed too high, but after about 15 minutes, I got the temp down from about 158 (I think) to 153 and kept it there for an hour.
My question is, is it possible that I just have too many unfermentable sugars because of a missed mash temp? If so, that's OK (learning experience). And if my SG hasn't changed in >24 hours, should I just assume that this is the problem and bottle? I don't want to re-pitch, especially if it is done fermenting, because I would have to wait another 2 weeks to brew another batch. I also don't want a bunch of bottle-bombs. Thanks for your help.
Other than this, the beer looks and smells fantastic.

 

[rocketman768]

You're right: it might have to do with unfermentables. However, usually, it is sufficient to make a large (1 - 2 liter) starter for your yeast to avoid any attenuation problems (as well as off-flavor problems). Just take a sample and taste it to see what you think.

 

[PurdyGood]

I forgot to add, I fermented at about 70 degrees in an Igloo Ice cube with frozen water bottles to control temp. It's hot down here in TX!
Thanks again.

 

[JLem]

my first two batches stalled at 1.020 and both came out fine. You're probably OK to bottle.

FWIW, after looking around this forum, I have attributed the 1.020 stall in my batches to 1) underpitching and 2) poor aeration. Since those first two, I've started making starters and aerating vigorously and have been hitting expected FG.