That is typically the opinion held of the more poisonous varieties that can kill a human being or those who simply know nothing of the animal. That aside, I think it is ridiculous to avoid using a certain species solely due to the fact that some people have an irrational fear. I'm terrified of certain spiders and a lot of people in the world are as well, yet you see them cropping up as fantastic characters in some incredibly popular literature. Not to mention that by avoiding the usage of certain species (in this case snakes), it only helps to perpetuate the idea that they are disgusting, filthy animals, since no one will take up the mantle of putting it straight when it comes to media. Ignoring wildlife experts, of course. Though they seem to be more concerned with alligators, crocodiles, big cats and sharks currently.
If you want the character to be a snake or any other reptile for that matter, go for it. Just make sure you have the species you desire to use researched to its fullest, as you should do with everything in any work you may be writing, and see if it works. If it winds up her being a snake simply does not fit the story, fine; change it. However, to not even give it a shot because of how a few people see the animal? I'll point to Fluffy's comment for what I think about that.
Besides, your main character is a raccoon, which a lot of people see as a disgusting pest and have a large stigma to them as well. Yet you are not even entertaining the thought of changing them. Why should you do so with this?
