born without an adult tooth on my lower 2nd premolar. Have some bone loss and tooth may need to be pulled. Bridge or implant?

An implant is typically the best option, but it's hard to say without seeing you in-person. An implant is a titanium piece that goes down into the bone, which should last you for the rest of your life! You're also only dealing with one tooth. With an implant, we typically suggest bone graft and membrane, which helps to build up that bone loss, so the implant holds steady and secure in place.
With a bridge, you're tampering with multiple teeth, some of which are most likely healthy teeth.
It really depends from person to person, but an implant is typically the best option.