Excellent play. You played the opening perfectly. I think players worry too much about opening theory and about learning by rote certain lines that they think will help them. Of course, at higher levels a knowledge of opening theory is pretty critical. But far more important is to have an understanding of opening principles - which you clearly demonstrate about that you do have.
Keep playing stronger and stronger opposition and if you keep winning you certainly shouldn't worry about opening theory. I do recommend looking through some of the classic chess games of the old masters - the natural way people learn chess is to start off in the style of the old masters and then move through the 20th century. Studying some obscure variation of a hyper-modern opening is not going to be much help to a beginner or to a player starting off. If you can find some early games from pre-1900 - hopefully that are annotated and explained - and look at these it will help you in your understanding of opening principles and your tactical ability. Tactics trainer on chess.com is also very good - don't know whether you have to pay to use it but it's good.
Steve
I have noticed that, on my current level, all I need to do to win a game is to avoid blunders, wait until my opponent blunder, and take the game. Simple forks, double attacks, counting mistakes, discovered attacks etc. seems to be very effective.
When should one start to study opening theory etc.?