Am I too young for my hair to thin or am I doing something wrong?

I (21F) noticed my high porosity, 3b/3c hair thinning and getting really dry. I don't know what to do.

I've been using the Curlsmith conditioning wash for regular wash days and then Ouai detox shampoo and Ouai fine hair conditioner for cleansing days. I sometimes use the Curlsmith double cream deep quencher for a hair mask and then wash it out after 1-2 hours.

To style, I do wash and gos and use Curlsmith light weight cream and gel souffle. I diffuse on medium heat. But, my curls only last a day or two and then I usually slick it back in a pony tail or bun until wash day at the end of the week.

Now, my hair is starting to thin on the right side and my hair overall has been dry and lifeless. I don't know if I should change my routine completely, try protective styles, or try supplements for hair growth.

I just need some advice. Thanks :)