While I am ashamed to admit, I didn’t understand the Real Presence until I was a retread college student in my mid 20s who accidentally stumbled on a good Catholic Student Center at a state college - that brought me back to the faith. (I had planned to become either Episcopalian or Methodist, even though I grew up Catholic and served as an altar boy nearly every Saturday night from the time I was 12 until I was 18. I was also an usher during my early 20s as a “one hour” Catholic who was struggling with “do I want to stay Catholic?”, “why am I Catholic?” - and this was after I spent a few years at a “Catholic” college).
Yes, understanding of the Real Presence is key. For children, 7 years old is considered the age of reason. I also frown upon parishes (yes, this went on when I was a kid - my younger brothers didn’t partake in Reconciliation until afterwards) who let children go through the First Eucharist without receiving Reconciliation first (while this is not as common as it once was, it still happens in some places). It’s not about getting out of the pew and walking up to receive - there is something else there - children and adults need to know this, not just go through the motions (been there, done that, hello).
My father was Methodist, and his church had symbolic communion once a month, usually with grape juice for wine and wafers for bread. I have heard some of the Presbyterians do this too. For them, it’s symbolic - it’s not sacramental. After my reversion story, if I attended a Protestant service (although I did go to Catholic Mass to meet the Sunday obligation), I refrained from participating in the communion service.
This is also why Catholic children are required to go to Mass. In Protestant circles, it is normal for Methodists, Presbyterians, Baptists (and I think Lutherans - I have a family member who is Lutheran) for the kids to go to Sunday school while the parent(s) attend the service. Several of my friends growing up did this, since it was conducive to their faith - and my Methodist and Baptist friends could quote much more scripture than me.
As a religious education teacher, we have talked until we are blue in the face that CCD doesn’t count as Mass.