Don't be such a crybaby. Well, you could. That's one solution. But there is a better one. Have a close look at the numbers 20 to 29. What do you notice about them? That's right: they all start with "twenty". So if a number is between 20 and 20, you can display "twenty", then subtract 20, leaving you with a number from "one" to "nine".
Don't try to do this all at once. This is a common beginner mistake and no professional programmer writes a complete program in one go. Start with something small, i.e. 1-19, as I already said, then you can add to it. 20-29 will need some new code, but that same code can be reused, with a slight change, for 30-39 (print "thirty" then something between "one" and "nine"), 40-49 and so on up to 99. Then add code for 100, and you'll see you can reuse some of the existing stuff, for example 129, you print "one hundred", then you can reuse the same bit of code that printed 29, which itself reuses a bit of code that printed 1-19.
But I've said all this already. Start simple, and build on it. All complex programs can be broken down to a simple start plus a series of manageable changes, and that's certainly how I always write code.