So the object here would be to stat up myself as a idealized version circa 1988 and then make up the character that version of me might play in a Pathfinder game at 12th to 15th level.
I don't know how much of the skills and knowledge I have in the real world would be of benefit in a fantasy world. A few basic hunting, fishing and camping skills largely based on guns and gear not available in a fantasy world would be of marginal benefit. I guess knowledge of germ theory, hygiene and first aid might help keep my fantasy character alive. Rudimentary skills in construction, well drilling and keeping old cars running I had from the jobs I had while getting my education would again be of little use without modern gear. Perhaps knowledge of math, reading and simple chemistry could have some application.
I know the rough formula for black powder and could distill the sulfur from foul smelling water and make willow charcoal, but I don't know how to get the nitrates from bat guano which is 75% of the formula. Nitrates were used in food preservation way back, so we might be able to buy them or at least find out how they are obtained. The Corning process would also be trial and error. That might be useful I guess. I don't know that I could design an effective gun even with the powder, but I could definitely put together some bombs.
What other skills might be useful?