I was into herps at a young age as well. I did informal talks with live herps to different groups of kids including summer camps, church groups and schools. All of the talks were done at the request of friends, acquaintances or family.

Mostly I would try to gear the talks towards herp conservation. For example: herps eat pests like rodents and insects and without the herps there would be an imbalance with an abundance of pests. If you have a crowd partication time and question/answer session you can easily have yourself a 30 minute presentation.

Good luck and happy herping!