I'm 50 now and have done a lot of solo travel, including Laos, Cambodia, Jordan, Malaysia, Canada.....I've often stayed in hostels - and felt like everyone's mother! met some great people though. I don't like the idea of being tied to a group holiday personally, firstly I want to be able to do what I like and secondly what if I don't like the other people?
My advice for feeling more confident is to sort as much as you can before you go. Book all your accommodation - hostels are great if you go to Asia particularly, plan how to get there from the airport, get your head around local transport, find where ATMs/supermarkets/restaurants are. Keep your first trip easier to build your confidence - go somewhere where English is spoken, or that is firmly on the tourist trail or that isn't too far from home ie in Europe.
Do it and have an amazing time!