Under attenuation

So I am a fairly new brewer I have done 3 extract batches so far
And I can’t seem to get any beer to go below 1.020 I have a Irish stout
In primary that has a sg there for a week should I just rack to secondary
And age it like I planned or give it another week so far primary had been 3 weeks

If it has been steady for a few days and isnt getting any lower you are probably done. Try giving the fermenter a gentle swirl or maybe even moving it to a slightly higher temperature location for a day or so. If that doesn’t get any fermenting action going then you are most likely as low as you are going to get.

Did you use dark extract? If so it probably won’t get any lower than that.

Here lately, a lot of extract brewers have been commenting about high finishing gravities. Try doing a lighter style with a lower OG. Some of my batches have finished at 1.020 but their alcohol content is in the mid to high 6’s. IME, a 1.020 beer, with the right balance of malt, sweet, and hops is achievable and delicious. 1.020 is not too high, especially if you’ve dropped 40 to 50 gravity points to get there. My suggestion for your batch is warm it up as mtodd suggested for a couple of days. If the gravity is still the same, proceed with aging.