I created Gmail accounts for all three of my kids when they were infants. They're now 7, 13, and 15, and the fact that they have accounts makes it SOOOOOOOOO much easier to share them content they may care about in the future, like family vacation itineraries, congratulatory or welcome emails about specific events or achievements, copies of school transcripts, and perhaps most importantly, photos & albums. Now that the older two also have phones and have their own personal needs for email, it's convenient that they have established accounts based on their names that they can use, and I use Family Link to manage their access to stuff.
Whether you choose Google products, Apple products, or something else entirely, I heartily recommend creating accounts for your kids when they're young.
Sounds cool but that vacation itinerary isn't as meaningful to your 7 year old as it is to you. Also sounds like a nightmare to manage and a liability when Google decides that 7 year olds can't have accounts so it's deleted (PayPal blocked my account after 15 years because they found out I opened it when I was a teenager)
If you want to preserve documents, keep them in your own drive/cloud and share the folder once they're capable.
Also once they use/need an email, they probably don't need one created by mom 12 years ago already filled with junk that isn't theirs — just my opinion though.
Google lets you create kid accounts and manage them within your family entity, which also then allows you to share purchased apps with them, share Youtube/Music/TV subscriptions, etc. When kids get to be 13, you can convert those accounts to full accounts (but still optionally manage them using Family Link).
I don't care if things like vacation itineraries and emailed stories about the things we/they did together when they were small matter to them or not. We're just giving them the opportunity to make that decision, rather than not have those memory enhancers at all. My wife's family basically never kept anything, and my dad's house burned down with all our old printed photos, kid projects and keepsakes in it. It's easy to mitigate some of this potential loss through digital means.
Whether you choose Google products, Apple products, or something else entirely, I heartily recommend creating accounts for your kids when they're young.