Thank goodness for a few sensible posters on here like Johnny5isAlive!
You obviously all know your own DCs but what's all the hysteria about children over 3 choking on small toys!?! Toys with potential small parts state "not safe under 36 months" in order to give a HUGE safety margin - in reality, the average child will stop putting random things in their mouth WELL before that - mine certainly did. And OP didn't say she was leaving the house FGS, nor that she was in a drunken stupour / coma! It would probably take her about 10s to come running if there was a problem downstairs.
Have we really got so nervous that mums are expected to hover over their PFBs (and younger offspring) every second of the day? No wonder there are so many threads about DCs who are insecure, or reckless etc etc. I'm pretty sure this isn't how any of us grew up!
OP, I think you're absolutely fine. At that age, inspired by a close relative with older children who had been doing this for years, we dedicated a low level kitchen cupboard to the children and filled it with plastic cups, bowls, plates etc, plus made sure their cereals, milk etc were also available at low level. They would wake up, go down and make their OWN breakfast - yes, sometimes there were spills to clean up, but what a wonderful way for them to learn a little independence! And yes, they were also able to put CBeebies on by themselves. We would come down half an hour, sometimes even an hour later. Of course they could come and tell us straight away if there was ever a problem, but guess what? They almost never did, as they relished their independence, and so did we. These poor neglected children are now growing up into lovely, independent young people, and I would absolutely do the same again, given the chance.