Like you, I too have a 31/3 extension date, I also booked in February and flew earlier in March, and know my flight registered, but also do not yet have the extension. Electronic membership card still showing expiry March 2021. Only a couple more days to wait to see what happens next.
I'm pleased to have the extension, but honestly it won't be of much use to me unless I can travel overseas before 31 March 2022, which I am not currently feeling very hopeful about. I took advantage of the current DSC offer to book flights to Qld in June to see the family - and 12 hours later, Brisbane is in lockdown and Qld Premier is saying get used to it, it's the new way of life. So I am pretty reluctant to be booking too many other domestic flights. All of which means I'm likely to start member year 1 Apr 2022 - when I might actually be able to do some more usual flying - as a LTG. First time I won't have been WP or P1 for 13 years
. So I really hope that Qantas comes up with some other ways to support status.