I think it's awesome that you are trying to instill a good impression of snakes on your students! As a prospective high school biology teacher myself, I am wanting to do the same, but the students of the age you teach are certainly the best ones to do it with. I've done two educational shows about snakes for two different groups of people: one group of paramedics, and one group of 3rd graders. The 3rd graders were by far the more interested, open-minded group of the two. Instead of revulsion, most of them showed complete fascination. The adult paramedics, on the other hand, tended to, if anything, want to move further back into the room... So yeah, great job, and I wish you the best of luck in your attempts. I probably don't have to say this, but be prepared for an angry parent or two to stop by asking why you taught their child 'lies' about 'evil' snakes.
Now, to get to your actual question, baby snakes can be called any of a bunch of different names. The most commonly used ones are hatchlings (if they came from an egg that is, live birthed babies shouldn't be called hatchlings as it is rather misleading), neonates, and later on, juveniles. I probably wouldn't call a very very young snake a juvenile. Usually I reserve that term for snakes a few months old or so. Hatchling and neonate are the two terms most commonly applied to newborn snakes. Even newborn would be fine to use. There are no sex differences in terminology, just as there are no sex differences in most snakes. I hope this was of some help.
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Chance Duncan
http://www.rivervalleysnakes.com