Teen mothers/young mothers?

I had my daughter when I was nineteen. I went out rarely, and even though I lived with my dad and he paid the bills, I still rarely did. If I did it was for a date, and that's actually how I met my husband Lol...different story...My dad watched her for me when I went out but he didn't mind because I went to school full time online and was a great mom...now that was me at nineteen...fast forward a couple years to my husbands older sister...she feels totally entitled to going out, does it often, like twice a week, constantly leaves the kid with her mom and even when she is around does nothing for her baby...and she always says how its hard being a single mom and she never gets to do anything...blah blah blah...and get this she's twenty seven. So I'm not sure if age is a factor...it certainly wasn't for me!!