Absolutely not! I had no experience whatsoever before booking my first background acting gig. They don’t require experience, they are mostly looking for specific ‘looks’. When you sign with a casting agency they will take your picture and you will call in to tell them that you are available for a specific show. They will not ask you anything besides, “First five” which are the first digits of your social security number so they can look you up. They will take one look at your picture and either approve or deny you based on the picture you took when you went to sign up.
After you are selected you show up with the appropriate wardrobe and all you have to do is be quiet and follow directions and you will be good.
Don’t stress about it! It’s actually very easy and a lot of fun. Some people completely support themselves through background acting but you have to be tenacious and have a completely open schedule.