I'm still waiting my refund.

I worked in 2021 and completed my tax refund forms through TurboTax on January 28, the IRS accepted my federal and state tax return on February 18, but I still haven't received my refund. I check the status of my refund on the IRS website every day, but it still says, "Your tax return is still being processed. A refund date will be provided when available." Why it takes so long?