My mom and dad were 27 and 30 when they got married and had me a year later. They were both teachers and low income. Upper-lower class? - I believe they did own a small house, but they incurred a lot of debt.
My in laws got married at 18 and 20 and were extremely poor, living in a tiny apartment with milk crates for furniture. They didn't have DH until 11 years later, and BIL 13 months after that! FIL is the smartest man with money I have EVER met. I don't know how he does what he did. DH says life was really, really lean growing up. Somehow, on something that would be equivalent to a $30,000 salary today, MIL got to be a SAHM, FIL sent both boys to (an EXCELLENT) private school K-12, bought them both nice used trucks (DH is still driving his 10 years later!) and paid for their college. He paid off his mortgage very early, and didn't finance a car after age 30 (buying new). He funded an extremely nice retirement. Then when the boys hit high school he got a big raise and promotion and pretty much feels like he's living the high life now.
We got married at 23 and 24 and are having the first kid at 25 and 26. We make a nice living and live comfortably. We have a very nice house. It
feels like the budget is really tight, but it reality it's not. When I realize I have $100 a month for home improvement, $130 a month for eating out, and $100 for clothes/whatever + an 8-month emergency fund, it hits home how blessed we are.

Really, we are doing so great though because of the traits DH learned from his dad. That and DH chose a career that makes him twice as much as either set of parents made when they got married.