There are arguments against TDD, some valid and some not. It's quite possible that you've heard some of them before, and likely that you've repeated some of these yourself.
Of course, testing takes time. Writing unit tests takes time. Adhering to the red, green, refactor cycle of TDD does take time. But, how else do you check your work if not through tests?
Do you validate that the code you wrote works? How do you do this without tests? Do you manually run the application? How long does that take? Are there conditional scenarios that you need to account for within the application? Do you have to set up those scenarios while manually testing the application? Do you skip some and just trust that they work?
What about regression testing? What if you make a change a day, a week, or a month later? Do you have to manually regression-test the entire application? What if someone else makes a change? Do you trust that they were also as thorough in their testing...