But I also think a lot of people, especially women, reach an age where they try to convince themselves that they're happy not being married because they need something with which to deflect all the prying questions and raised eyebrows from people who assume there must be something inherently wrong with you if you're over 30 and not married.

Without going as far as talking about marriage, yes, this is a very common behaviour where people will "appropriate themselves" the rejection they face, as a coping mechanism.
It's easier to reject yourself before anyone does it when people tend to reject you.

A lot of the people who claim right, left and center they are "single and happy to be!" are in reality simply not on anyone's wish list. Then they get busy and pretend that they don't have time for relationships, whereas they secretly crave for a relationship but relationships don't come to them, instead they get rejected. So they go further in their madness.
You can spot these people when at the slightest sign of interest from a potential partner they don't hesitate to leave their busy lifestyle the next day and are all over this person.

You will never ever get someone to admit this though. These people are lying to themselves, otherwise they would just have to admit that their life is a big pile of poopoo - but that would go against their coping mechanism.
The areas where you will see that often are marriage, children (No, I have never wanted children! says the woman who realises she will probably never have them), relationships (I just haven't found the right person!).
I guess it's easier to say that than to admit our failures.

I guess I'm lucky that my parents don't pressure me. I'm also lucky that both my brothers are in long term hopefully the "one" type relationships and that at least one couple will hopefully produce grand babies one day.

As for society yes I get it sometimes that..you're a great catch...why are you single..why haven't you managed to even have a bf yet.

And the problem is..I WANT one (a Man, a Husband/bf, partner in crime, lover, friend ect). I want babies, and at 36 every month that passes means one less chance of being a mom in a relationship like my parents had which is what I would like.

But I can't change the past and the fact that I spent my best "dating" years being the size of a house and very unattractive to the opposite sex...I can only be me now, keep healthy and live life. If I'm alone so be it. I will have missed out on something I would have greatly enjoyed in being a parent. But I'll get dogs and friends and make my own weird little family that way I guess.