My fiancè doesn't know adulting?

My (29f) fiancè (29m) just got engaged and are discussing marriage plans. He didn't know that the official marriage is the signing of paperwork and thought that the wedding celebration at the church is marriage, he also doesn't know what a prenuptial agreement is, or what paternity/maternity leave is. He was raised here all his life, went schooling here etc.

I am shocked at this, but I love him so much, he's so sweet and is really protective of me.

Updates
1 y
But not knowing what marriage is is very concerning. Should I wait before getting married- I feel he should figure things out before jumping in and raising a family
My fiancè doesn't know adulting?
Post Opinion