Eeeek!
As long as there are no poisonous snakes in your area don't worry. They won't hurt you and are good for the garden. We have a pond we made several years ago. Lots of frogs. A snake got hold of one of our frogs and I had to pull the frog out ot the snake's jaws. Mr. Kedd was too creeped out. Only time they would make me nervous is if I lived in a area where there were killer snakes.
One caution. Garter snakes can bite. I had one bite me once when I was showing off about how I wasn't afraid. I picked up the snake and didn't hold it close enough to the back of the head. He (or she) drew blood but it really didn't hurt. Just like a little scrape.