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Are these goals realistic/possible?
If you're dedicated and don't have anything else to do (like work a real job to survive), probably.
. . . in December of this year, hopefully, I will be able to make an app for Android . . .
Entirely possible. You could make your first "Hello World" Android app tomorrow, but I support you building your Java knowledge, confidence, and proficiency before starting Android programming.
. . . make tutorials for people that bring all of the knowledge they need into one place . . .
Don't do this. I'm not sure what this is about. It's been done a thousand times, rarely well. Focus on building your own knowledge, help others when you can and have the time, but don't expect the be the source - or even collect in one place the source - of all info anyone will ever need. It's a bit silly.
Good luck! I mean that sincerely. Chances are you'll make several attempts before becoming successful, but persistence pays off. Don't become discouraged, believe in yourself and your ideas, and have a regular job to pay the bills.
By next year April, I want to have made a good game, or have a game in development.
If this is related to number 3, it needs to be your focus, then #3 may follow. (How are they related, and what's the timing?) A successful game - however you define success - is rarely the result of one person's efforts. It takes a team of people with different talents. It's a little bit like creating a hit song. Getting a Top 40 hit might happen from one person's efforts, but it's usually a group effort.
Don't be a stranger. Keep us posted on your successes and failures. We're here to help. (But no money or expectations of sharing the profits.)