I don't think it's very likely for me to...

[Silverobama]

I'm getting older and this year I'm 37. Soon I'll turn 38. I'm disappointed because as the year goes on, I still can't find a girlfriend and let alone a marriage. I told my friend "I don't think it's very likely for me to marry because I'm almost 40." in a sad tone and try to gain some support from them. Is my sentence natural?

 

[emsr2d2]

I'm getting older and this year I'm 37.

Everyone's getting older with every second that passes. I'd omit the first four words.
Do you mean you're already 37 or you'll turn 37 this year?

Soon I'll turn 38.

You'll turn 38 exactly one year after you turn/turned 37!
If you're already 37 and your 38th birthday is in a month or so, then "soon" would work.

I'm disappointed because, as the years goes go on, I still can't find a girlfriend, and let alone a marriage wife.

I would omit "as the years go on" and say "... because I still haven't found a girlfriend, ...".

I told my friend "I don't think it's very likely for me to marry that I'll [ever] get married because I'm almost 40 no full stop here" in a sad tone voice and to try to gain some support from them. Is my sentence natural?

Only put a full stop at the end of a quoted sentence if it also marks the end of the surrounding sentence.