My first children's book was rejected 25 times. Then it sold, and went into four printings. In the course of my career, I have received enough rejection slips and letters to paper the walls of my house. A writer needs a lot of hope. A writer must also accept reality.
Writing is an art, a craft, a profession.
It is also a business. Of course you should. It isn't easy to get an agent, but it can be done, with persistence. The best way is to get an appointment with an agent at a writers' conference, while at the same time having completed a wonderful book. Agents are wonderful people.