I am the eldest of 3, and there's a 5 year span from oldest to youngest. My two kids are 4 years apart. I liked the spacing. My oldest had a lot of one on one time with me for the first 4 years, and had started preschool before his sister was born. My daughter had a lot of one on one time with me too as her brother was in school. They were not close when very young due to the age gap, but they became very close in the teen years and remain so.

My sister married a widower with 3 sons then in their 20s. She and her husband had one baby, also a boy. He is 11, and his older brothers are now all in their 30s. They dote on him and he adores them. They are a very close family. The older sons have their own homes in the area and stop by all the time to spend time with their youngest brother.

I have a cousin that had her first at about 19/20. Not planned, but she was still ecstatic about the baby. She didn't have the next child until she was about 28 and had the last when she was about 42. She did a great job raising all three of them, though... well, she's still raising the youngest, but she seems to be turning out quite well.