I would probably say 4 to 5 years from seedling to fruit in Michigan. They recommend you plant two or more for cross pollination. Once they get established, you will likely end up with a spreading paw paw patch. I’m not sure if mine are spreading by seed or by roots, but they’re definitely spreading. Paw Paws are one of the first trees to flower (deep purple flowers) and are pollinated by flies. Bees don’t’ work them.
One thing I’ve observed about paw paws is they aren’t all the same. Some trees/cultivars produce premium large fruit in abundance like in the photo above. Other trees produce small fruit in a sparse fashion. I started with two trees. One I bought in Memphis, TN and one I bought here in Michigan. The Michigan tree was a clone (ie graft) from Paw Paw development they do at Michigan State University. That tree produces nice big paw paws and has very nice fall foliage (yellow) and large leafs. The Memphis Paw Paw tree has grown like crazy and is covered with blooms in the spring, but only produces a few small paw paws. It also has poor fall color.
So beware there is a large variation in the quality of paw paw trees. I would recommend buying a named cultivar. My Michigan State paw paw is a graft, whereas my Memphis tree was just a regular seeding (no graft). My Memphis Paw Paw will probably meet up with the axe soon. It’s grown big and just isn’t as nice of a tree.