What is the reason the optometrist said you need glasses full-time?
There are plenty of possible reasons, some are not so important, others are very important.
You don't notice your vision is bad, it doesn't mean you are not straining your eyes all the time. Possibly you strain your eyes so hard it is actually better for you to wear glasses all the time for a while to let your eyes rest.
You should talk to your optometrist and find out why they say you need glasses full-time.
As an optometrist, from my experience there are only few cases you actually need glasses all the time when you don't really see a reason to.
When I was 13 I discovered I needed glasses, started really wearing them only at 15-16 when I could no longer see the board even from the closest place in class. Not wearing glasses when needed caused me to develop a fatigue issue, my eyes get tired quickly even from reading (I am shortsighted, so up close should not be a big issue), I have astigmatism too, but the main issue that was probably caused by not wearing glasses when needed is that I can't wear the full correction for up-close and need a lower prescription for up close.
When I was wearing glasses only when really needed them my vision even improved, when I was wearing glasses full time or not wearing them enough it only got worse.
So it is very important to know why you need the glasses.
Now, I'm almost 30 and my vision is almost back to what it was at 15. Slowly improving. I wear them when needed, even have some pairs with different prescriptions and one progressive pair.
Lately, though, I started wearing them more often... felt I need to despite the recent improvement....
Why do you worry so much about needing glasses?