Need some help with strength training

Sarauk2sf

Try the various calculators on this website for your BF%:
http://www.fat2fitradio.com/tools/

I'm with Sarauk2sf - 38% sounds way too high at your height and weight.
The best methods for BF% calculation are getting it professionally tested using hydrostatic displacement/Bod Pod, or a DEXA scan. Next best is using calipers by an experienced qualified person, circumference methods can probably get you +/-~4% accuracy, unless you are very fit or very overweight. Least accurate is bioelectrical impedence.

This calculator says my bf% is 26.9

That makes far more sense, They are not totally accurate and will only give you an idea/ballpark - but there is no way you were high 30's.

Sarauk2sf

Changing your exercise selection from week to week is a good way to make it difficult to impossible to track your progress. Vary what you are doing by adding weight and\or reps as frequently as possible. A beginner on a proper 3 day per week full body routine should be able to add weight every workout (yes, every workout) If you are eating a deficit you will eventually stall though.

Just one point - you may not be able to add weight on every workout but you should try to add reps. For example, try for x sets of 6, then x sets of 7, then x sets of 8 - when you get there, go back down to x sets of 6 with a higher weight. Although, I agree that for the first couple of sessions, adding weight each time is probably achievable. The amount/frequency you can add will often depend on the type of lift also.