I never saw being happy in relation to others.
You are happy for your own self.
And just like one shares the cheer of the winner in any event... it is normal that if it makes you happy, it will make your parents happy.
I'm 44, my eldest son is 20. This is the one and only thing I've told my son all his life "you are free to do with your life what you will, the consequences of your actions are yours to keep".
There's a difference between living up to other's expectations and making anybody happy.
You can achieve to live to other's expectations, but to be happy is a personal decision. And most people, sad to say, find very good reasons not to be happy even when everybody had fulfilled their wishes.
Be happy for yourself, and if you live under your parents roof, abide by their rules. But don't make it about making anybody happy, because that is a very personal decision.
On the other hand, beware of being unhappy just because loved ones are unhappy, especially when you have done everything in your power.
I have other two children, she's 10 and he is 8. Every morning I tell my son to pay attention to his teacher, and I tell my daughter to have fun. She's set on rules and obeying. She won't even talk when the teacher leaves the room. I tell her this is not normal. At 10, she oughta live it up a little.
So there you have a mom telling a daughter not to be too good.
It's all about a balance. There is something in you that tells when is enough, listen carefully to that voice.
Happiness is those decisions that carry desirable consequences and create agreeable circumstances. Happiness is an attitude, is what you make of what Life throws you with, straight or curve balls.
And if I were your mom, I'd be proud of you just for asking this question. So you're voted up in my book.