Trust set up-things I need to know, if it’s worth it

I got quoted 3k by an estate attorney yesterday to establish a trust with my husband. We have 1 toddler and another child on the way and I want to make sure they receive the money at a later, more responsible age, and that it’s been invested so it can grow. I also want to make sure their college will be paid for. We don’t have “much” (not 7 figures) but between everything we have about 400k as of now at 28+30 years old. I feel that it’s worth it, it’s just hard to pay 3k up front out of pocket. My MIL is older, and my SIL is too busy to responsibly handle the funds for my children, I feel. Which is why I want the trust, I don’t trust them to be the beneficiaries of my life insurance policy, 401k, home etc.

What do I need to know going into this?