It will come when it is supposed to come.

And you can't rush it.  The creative process, that is.  You can and should work on whatever inspiration that manifests itself for you, and you can and should do research and absorb yourself in your interests, to the extent feasible and with a bit of balance for other necessary aspects in your life.  But we are all getting older, and there are opportunity costs everywhere.  There's no way for us to accomplish everything we want to accomplish without excluding other items/goals, and part of trying to do something, following whatever inspiration does come, is that we won't be able to follow every inspiration.  That we'll have to make choices.  That's okay.  Let's not try to hold on to the past or to the present in such a way that our future suffers.  Of course, part of the trick is that we don't exactly know what to hold and what not to hold, but that's okay too.  We're not perfect.