Try using your degree once you graduate. You'll earn a wage whilst building up experience in your field.
Then start training part time.
If it all goes horribly wrong or you realise (however long it takes) it's either not for you or you're not going to get a flying job then you have something to fall back on.
If you leave, go into training, then it all goes wrong, you've got a lot of debt, nothing to show for it and just a degree you did years ago with no relevant work experience.
Good luck whatever you choose. Keep your options open, don't burn any bridges and take the least risk option where you can.