In reply to TravisTheHuman :
Call an estate attorney and tell them you want to setup a will.
Can be as basic as "everything goes to my kid, full legal name" or as elaborate as necessary. Or in my grandfather's case, his will just said "see the trust" because trusts are private (until the estate tax return is filled) and will's are public, and he was dividing up $8 million in assets he didn't want anyone to know about between 6-8 people.
Being listed as a beneficiary is good, but, talk to an attorney and see if changing that to a trust would be a better tax move for the kid.
Update as needed. Got remarried? More kids? Financial windfall? Decide berkeley the family, everything goes to X church or Z charity? Update then.
Make sure someone knows where it is, and when you update, let them know. I don't have E36 M3, but there's a copy of mine in the gun safe, my mom has a copy, and my best friend has a copy. If I kept a lawyer on retainer, they'd have a copy too. The courts will enforce the most recent date when the time comes.