Your own Opening

There is no such thing.  I guarantee you that whatever you play as been played before, even if it's not played by the upper tier players whose games you find in databases.

Take my game from last night as an example.  After 1.d4 d5 2.c4 c6 3.Nf3 Nf6 4.Qc2 dxc4 5.Qxc4 Bf5 6.g3 e6 7.Bg2, we have a position that has been played over 1000 times amongst games published in 365chess.com alone!  This does not mean it's the only 1000 times this position was ever reached.

Out of those 1000, the move 7...Bxb1 was played exactly zero times!  Does that mean it's never been played?  Of course not!  I didn't invent 7...Bxb1.  I guarantee you it's been played prior to last night.

After 7...Bxb1 8.Rxb1 Qd5 9.Qxd5 exd5 10.Bf4 Nbd7 11.O-O Ne4 12.Ne5 Nxe5, White Blundered by playing 13.Bxe5??, allowing 13...Nd2 winning an exchange.  Black won in 28 moves, including a second blunder by White on move 27.  Does this make the move 7...Bxb1 a novelty or "my own opening"?  Of course not!  Again, guarantee you it's been played before by someone at some point, even if he was only rated 1600 or even lower!

It's possible for two people to independantly invent the same thing, like Calculus. If it's new to you it's new to you. That said learning chess theory instead of trying to reinvent the wheel will help you get further faster.

With more chess games than atoms in the universe at some point in some games everyone will reach a novel position. It's just not likely to happen in the opening. The further along in the game you get the more likley it is to happen. You're more likely to pioneer a variation of an established opening than something like a new way to play from move 2 or 3... try to look in lines that are forgotten or seldom played today, figure out why, see if the bust holds water or there's a fix... etc... that's one way to approach it if it's something you really want to do. Won't be easy, might be possible. 

Players who get credit for pioneering openings are unlikely to be the first person ever to have played the move anyway; they just played it well, played it often, demonstrated new ideas with it perhaps.

Some play in very original ways, in the UK there is Michael Basman, well was he doesnt play too much anymore, M Surtees is a strong player who plays very original chess openings and plans, has taken out a number of masters with his unorthodox play. In my local area we have a player Winston Williams who plays 1.c3 exclusively as his opening move which is pretty out there but he is pretty strong also about 180/190 ECF 

Do not incorrect me, this are just my opinions on the annotations and comments. It is called the King's Pawn Opening: Asian Defense: American Variation