Hey,It could took you from 3 to 6u20137 months to get a change of status. Once, it is complete then only you are allowed to start and pursue your education in the US.But getting a COS especially from H1 to F1 in current market i.e. Feb, 2023 is not easy unless and until you have a very strong reason to start an education or an highly reputed employer who is funding your education and asking you to get a higher degree. Hope it would help.Thanks !!