I realized that I didn’t answer the OP’s question.
Extra curricular activities are important. They do make a more rounded individual, teach them how to interact with new people in different situations, and give skills not found in the classroom. This makes a better person, not just a better college application.
I look at my job as a parent to produce highly functioning, decent, self sufficient adults. It takes work, and sacrifice. The adult can be anything from a welder, to an architect, to a nun, to a doctor, or to anything in between. Just so long as they are an asset to everyone around them, and to society at large.
As to how much a kid is capable of?
My two oldest are a senior and a junior in a college prep HS. 3.7 something, and 3.999 (she’s pissed because she’s not a 4.0 anymore, and she’s close.)
Both work part time at teen age jobs ( They each bought their own cars, have to pay their own gas, insurance and any social extras.)
One was in cross country this fall, both helped me coach their younger sister in volleyball this fall, just like they have for the last 3 years. They both are in nordic skiing that just started. National Honor Society. AP classes. Boyfriends take up time, too.
Lettered in Lacrosse, academic letters, 3 captains between them, organized a blood drive, etc. etc, etc.
They also have household chores that have to be done before they can go hang out.
All my kids are like this. They seem to be happy, have friends, boyfriends. Not overly stressed, just that’s the way life is-this is what their peers are doing as well, so this is what normal is.
I think it’s cool, and not quite sure how I got so lucky.
They also wreck stuff, steal my clothes, get in trouble with school on occasion, sneak around, and take way too many risks.
I don’t micromanage, or do their homework-I’m too damn busy myself.
But they know that we have expectations that they must fulfill if they want to have any of the good stuff. Grades are one of them, and non negotiable. Anything lower than a B and your freedom is greatly curtailed.
My 44 year old healthy husband suffered a stroke this summer, and was in the MICU for 8 days. He was expected to die-we had the chaplain and the private room at the hospital. It was terrible. He has since recovered pretty fully.
I was really glad during that awful time, and staring directly at impending widowhood, that the kids were taught from a young age to do what needs to be done. Whether it’s grades, or work ethic, or compassion. Even if the worst possible thing happened to our family, I knew we would be ok.
I digressed, but I guess my point is, it’s not just the grades, it’s the expectations.
Have high expectations for your children, you’ll be pleasantly surprised.