nachoqtpie - if I may say so - and I say it with kindness, and don't mean to be rude - but - you worry too much
Its just a hair wash. If it doesn't feel right then, quite simply, you do it a little differently next time. If it doesn't feel clean this time, then wash it again - either right away, or a little sooner than you usually do. Nothing to be nervous about; lots of people use baking soda on their hair - for some it works, for some it doesn't - but your hair isn't going to fall out, or catch on fire, or turn green. At the very, very worst you will just need to wash it again
I have long hair - waist length at the moment, but I recently had DH chop about 6" off. I have an old shampoo bottle that I put about (
about, I don't actually measure) 1/4 cup of baking soda in, and then fill it with water; shake it up well, and squirt some on my scalp. I massage it in, and leave it for a few minutes. I also gently work what runs down into the length of my hair. Then I rinse, and repeat. I have another shampoo bottle that I put a glug (maybe 1/2-1/3 cup) of ACV in, and fill with water. I squirt some on my head, rub it in, run it through the length of my hair, and let it stay there while I finish washing the rest of me. Then I rinse it out. Finished! I find that sometimes my scalp doesn't feel quite clean at this point, but much better after my hair dries. I leave the bottles in the shower, and continue to use until empty - shake the one with baking soda before use.
I find coconut oil in the natural foods section at the supermarket, with the other oils. It is solid at low room temperature (where it usually is, in my house). I scoop some into a decorative bowl with a lid, and leave it in the bathroom. I smear a bit on my face at bedtime (very nice feeling!), and sometimes I will work some into the length of my hair, not my scalp. I do this the night before a shampoo, braid my hair, and let it soak in all night (towel over the pillow); but if that's too icky, I would recommend just working it in an hour or so before the wash. You will probably want to work some more baking soda sloution into the part with oil to remove it during the wash. Between the oil and the vinegar I find I have fewer tangles.
Oh, one more thing, I wash my hair about twice a week, every 3-4 days. That is all it needs. If your hair needs washing every day or two then you might want to just use the baking soda once per wash, rather than twice. I don't know for sure, but it might be too drying otherwise.
However, the best thing for you to do is, stop worrying, and just do it!

And keep at it until, either, you find what works, or you decide that it doesn't work for you, and then try something else.
