Hi naman10,
Without any referrals, as long as you can complete the daily checklist I would say you did the right thing
I spent a few months dithering over whether to upgrade to premium, but I am very happy that I did!
If you can complete the daily checklist, then you get a 16% bonus from whatever you earn as you know...so in my opinion I certainly think it is worth it, even if you only get a few tasks and 1 cent video's for a particular day, it all adds up and every little helps.
Of course only you can decide if premium membership is for you, but I would say yes, you did the right thing!
And I don't have any referrals either