Is this bad ?

My girlfriend is pregnant she had her first son when she was 17 she's 28 her son is almost 11. She feels like she waited too long for another baby she and her ex husband tried for a baby a few years ago but she had a miscarriage. What's bad me and her have been together for only a month she recently just got out of a divorce I got her pregnant after she divorced her husband. She said she feels different being pregnant now at 28 than what she did at 17. Her brother was 12 years older than her they hardly got along and didn't have anything in common now shes worried she's putting her son through that. Is this bad ? Is it wrong her son is gonna be 11 when he's a big brother ?