This is only my opinion mind you but if you're just learning to ride at 44 then a cafe racer is probably the last thing you need until you have some riding time under your belt unless you are just going for looks but 750's do make great cafe racers.
As a first bike..If I were to chose a first bike it would probably be a bit smaller but since you already have it, it should be okay. Just remember that big bikes are a bit top heavy at very slow speeds.
Many parts places online. Here are a couple of my favorites:
MRCyclesBabbittsHere is a link to the 79-83 CB750 service manual but you may need to register on the site to access it.
Honda Service Manual