Honestly a good friend is someone who will try to care or atleast understand your interests even if it doesn't reflect their own. If she's being willingly ignorant and controlling about the situation then I think it may be time to close the door.
On the same note you need to understand their fear. Can't just go one way. You like snakes so you're only seeing it from your end. We all have fears. She is entitled to her opinion. As you are entitled to own a snake.