I recommend putting all traveling bagged snakes into an "ice chest" (without ice) aka styro-foam box/"cooler", both to mitigate extreme temperatures in the
car (car seats get very hot from the sun, for example...and snakes get cold when subjected to our A/C that we may need) plus, think of it as a "car seat" for
a snake, if you have to stop fast? (I put a towel under them inside too.)
I've done many meet & greets with all ages: young children can be very "grabby" and either pull on a snake or squeeze them without warning...so keeping
them calm about meeting a snake, and explaining they must be gentle before you go forward is essential. They can hurt a snake without meaning to. Also,
for children that young, don't let them hold a snake by themselves: once in a while, they may drop the snake suddenly without warning! All ages actually
need to be watched closely, the way a "spotter" for a gymnast in training does.

I've never had anyone drop one of my snakes (& yes, I've let some hold
them by themselves only with me right there) but my snake-owning friend did- a kid dropped her ball python. Snake was ok, but this shouldn't have happened.
All in all though, I enjoy "meet & greets"...they're both fun & exhausting (for you AND the snake, lol). And teaching children while they're young & open-minded
really pays off.
Many years ago, I was invited to do a snake program for a "summer camp" of young kids with a variety of my snakes. The man in charge told me that while he
thought it was good that the kids learn about snakes, in all honesty he really didn't like snakes & he warned me that his own son was in the group & that I shouldn't
be surprised if his son was the first one to leave the room (in fear). Hilariously, his son WAS the first one out of his seat alright, but it was because he wanted
to get closer & to touch the snake I was holding.

Sorry, dad...
In an abundance of caution, you might also want to take hand-sanitizer &/or remind the children not to handle food until they've washed their hands after
touching your snake. (some places are more paranoid about this than others, ask the teacher... where I live now is an outdoorsy & farming area, & no one
brings up hand-washing)