What if the part after "depuis" requires l'imparfait or passé composé?

Question

Such as "Je joue du piano depuis j'avais six ans." Would it be more grammatically accurate to say, "Je joue du piano depuis l'âge de six ans."?

Accepted Answer

Hi Brittany,
You first sentence is incorrect. You have to say:
Je joue du piano depuis l'âge de six ans .

Answer

Bonjour Brittany,
It seems to me that in your first phrase  «Je joue du piano depuis j'avais six ans»  --> J'ai joué au piano depuis j'avais six ans -- would be more correct by using the passé composé along with l'imparfait; however, since playing the piano is a habit or something learned that is still ongoing, I would rephrase it to be Je jouais du piano depuis j'ai eu six ans due to the fact that playing the piano is a habit, learned skill that is continuing.  One caveat here, like a former French teacher told the class, the French language is not simply English translated into French.
And your second phrase, I believe is the most grammatically correct.
Bonne chance,