Transfer of UGMA Account into a Trust

Upon birth of a child, granfather bought a zero coupon bond that matures in eighteen years. The mother is the custodian of the bond. Bond is 2 years from maturity and the value will be $35,000. Parents have this earmarked for college. Concern here is the child getting possession of monies at 18. Can the bond be transferred (re-registered)into a trust designed for educational purposes so child will not have direct access.

Not without the kid's consent, once he is eligible. Some good news, in many states the kid gets the proceeds from the UGTMA at 21, not 18.

Two additional things. The child is only 15 right now. So, could this be done right now. Before they are eligible for the money.
As an additional thought, could we unwind the initial transaction and start over?