Welcome to the low end, dive right in, the water’s warm.
As has been said above, because you’re learning from scratch, having a missing digit is something you’ll work around naturally and you won’t be aware of any compromise. As to whether right or left handed, try a bass and go with what feels natural, just be aware that left handed players are not catered to nearly enough as they should with regard to range and availability but it’s not insurmountable, as many of our southpaw members will testify.