I would say that it is impossible to know unless you are already an Ariyan. The future is uncertain. If you do ordain, then give it your best shot. If, after giving it your best shot, you decide to disrobe, then at least you gave it your best shot. You can't ask for more than that.
Four types of letting go:
1) Giving; expecting nothing back in return
2) Throwing things away
3) Contentment; wanting to be here, not wanting to be anywhere else
4) "Teflon Mind"; having a mind which doesn't accumulate things
- Ajahn Brahm