"general era of one's birth" has a lot more impact on well... everything... About a person's life Way more than "time of year"
You are way more likely to be similar to the people born in the 5-10 years around you than to people born 50 years prior but in the same month.
But hey, as long as it's just for fun and you aren't basing major life altering decisions on things.... Why would I care if you like giggling at the little blurbs in newspapers about how ridiculous capricorns are when mars is in retrograde.
She will never forgive me for making her my mother's potato casserole.