Hi.
I was childless by choice until I was almost 40, too. I was so happily childless free (having a kid was never ever once in my thoughts before) that I was really shocked when I started feeling the desire. I waited awhile longer to see if it was a true want or just some weird passing hormonal phase before telling my husband. (he had always wanted kids but accepted that I did not)
So the feeling turned out to be real.. and yeah, we went for it.
And you know what? I conceived naturally within a year, had a dream pregnancy (no sickness at all!), and gave birth to a healthy (knock on wood!), sweet-tempered (knock on wood!) boy.
Only you know if becoming a parent is right for you. But if you do want to... go for it! Don't get caught up with potential negatives. It's one thing to be aware of possible problems regarding conceiving, pregnancy, etc... and it's another to *focus* on them.
If I can give a bit of unsolicitated advice, it would be that if you decide to go for it, then just continue living your life as you are now. (just minus any birth control measures you might be currently using, of course) Don't turn your life into "trying to become pregnant". That just causes unnecessary stress.
Good luck!