Delaying Childbearing: How Old is Too Old?

I didn't start my period until I was almost 18 years old. So I didn't loose a ton eggs in my youth even though they were aging right along with me. I didn't plan to wait to have kids. But not meeting my hubby until I was 28 and getting married at 30 made having baby #1 at age 32 and baby #2 at age 34 just part of our life. I didn't have any pregnancy complications and neither did the kids. I did end up with a C-section for both due to each one getting "stuck". Now at almost 36 we are have been trying for # 3 for 11 months with no luck. I start a cycle of Clomid this month. So we shall see how it goes. if no pregnancy within the 6 months they allow then I will just have to resolve myself that the 2 gorgeous kids I have are fulfilling enough. I can't complain when my sister is going through her 4th cycle of Clomid at age 38 and has had 2 miscarriages.