Good luck. I brewed 5 extract kits that I have notes for before I went AG, and none of them hit the "1.020 wall" that everybody talks about. Interestingly, many extract brews will show an FG of approximately 1.020 if you use a refractometer off eBay with a poorly converted SG scale. The higher the OG, the worse the skew. For example, I had a Fat Tire clone that started at 12.9 Brix and ended at 6.9 Brix. In the refractometer, that looks like 1.033 FG. Using a proper conversion calculator shows it's an FG of 1.013.
Those 5 extract brews that finished without getting stuck at 1.020 were using Nottingham (Irish Red), 1056 (Cream Ale), 1214 (Belgian), 1968 (Porter), and US-05 (Stout).