Dharma Sandeha

Respected members and experts in Dharma shastra, I am a Niyogi brahmin from Andhra. I am 22 and still not a dvija. Recently, I heard from a person on social media that upanayana is of no use for me and that I should do prayschitta for not getting upanayanam at the right age and that I am not eligible for any sadhanas or shastra adhyayanas. Is that true? What are the prayschittas for me? m I still a brahmin? did I lose my varna? My parents are planning to do upanayana next year.according to some people, Gayatri mantra Upasana will not be effective after 16 . Is that true? I am just confused.