I'm 50 and my life has also been ruled by social phobia since my earliest memories. From a young age I used alcohol to socialise which worked on a superficial level, I'm guessing you don't plan on becoming an alcoholic in your fifties though. Most people make friends through work, hobbies, church, volunteering, sport? Maybe joining a walking group, that always seems like a relatively easy option. Painting or some other craft so you can choose to chat or not.

I definitely think it's possible if you want it but you'd have to really find the courage within to start and importantly to maintain your efforts. You certainly come across as a very warm, kind and positive person so it's hard to imagine that you are having to deal with this. I think you should make a plan to perform one, two of three actions a day that would bring you closer to your goal.