Paying correct percentage of taxable income?

We don't know what product you are using--Online TurboTax or desktop software, which can make a difference when telling you where to look for things.   Or did you download/print your return?

I'm a fellow user.  I'll ask for some more info that others may want to know, who may further comment.  Have you looked at your Form 1040 and Schedules 1-3?  What line of your Form 1040 are you referring to when you say "Federal taxes calculated?"   The total Federal tax is on Line 24, and the self-employment taxes are on Line 23.  Other taxes may also be included on Line 23.  The figure there on Line 23 comes from Schedule 2.

Your return also likely has a Schedule SE, where the SE tax is figured.

TurboTax says:

"If you're self-employed, you're responsible for paying both the employer and employee portions of your Social Security and Medicare tax—a total of 15.3 percent on 92.35 percent of your net earnings from self-employment."   (That 15.3% includes 12.4% Social Security and 2.9% Medicare.)

The Self-Employment Tax
https://turbotax.intuit.com/tax-tips/self-employment-taxes/the-self-employment-tax/L8xXjolB4

Yes, you are in the 12% tax bracket for income taxes.

As for your self-employment tax, this is on top on income taxes and is calculated at 15.3% on 92.35% of your net self-employed income.