To efile you needed to enter the 2019 AGI from your 1040 line 8b. Too late to efile it now after you mailed it. The only way to know if the IRS got it was to get a tracking number from the post office when you mailed it.
The IRS is taking a long time this year even to just show up on their website. You are not alone. Millions are still waiting. Turbo Tax only gives you an estimated date. The IRS usually pays most refunds within 21 days. But these are not normal times. This year is taking the IRS longer to send the refunds. There are millions more people filing returns to get the Stimulus payment.
See this news article on Refunds being delayed
https://www.msn.com/en-us/money/personalfinance/where-is-my-damn-irs-tax-refund-new-answers-emerge-a...
Only the IRS can tell you. check IRS Where's my refund
https://www.irs.gov/refunds/
When will you get your refund?
https://ttlc.intuit.com/community/refund-status/help/when-will-i-get-my-irs-tax-refund/01/25589
IRS - Questions about Refunds
https://www.irs.gov/refunds/tax-season-refund-frequently-asked-questions
