@AtSea1979 I saw your post the other day but haven't had the chance to reply.
I’m 40 soon and I don’t want to be alone for another ten years like the previous ones. When I was in my 20s I never gave this a thought, it wasn’t this hard! Why is it now?
I turned 40 a couple of months ago and am in a pretty similar place, except without the relationships in my 20s 
. The answer as cassettes said is to jump in, but it can be much easier to say than do.
I think it pays to try and understand what holds you back, for me it's a core belief that I do not deserve to be in a relationship, there will be something stopping you, and it probably isn't the superficial excuses you make to yourself when you put it off.
I found I made most progress when I treated the whole process like a research project or job interview, try listening to some of the blogs that get mentioned on the thread, and read some of the books that get mentioned, even when they don't really apply to you, you will still find little details that will broaden your understanding of yourself and others.
Basically, make a deliberate effort to invest time and money in yourself and in understanding what you want and need.
Also, make sure you totally indulge yourself for your birthday, doing something nice and remembering what you do have really takes the edge off what can be a rather depressing day. It's only a number and it doesn't really mean anything, but I found myself more affected by it than I thought would be.