Would like to know if it is possible to start a digital marketing agency without much experience and still be successful by figuring things out along the way.
It doesn't hurt to learn the ropes on someone else's dime.
I started a web development company right out of school in 2002. The hardest part was winning business because I didn't have much of a network. If I were to do it again, I would prefer to work somewhere first for a couple of years.
However, if you can't find the right opportunity and you feel ready to start a business, then go for it! It worked out okay for me :)