Hi Hari. Taking a gap year won’t hamper your application in any way if you are doing something productive during the gap year and can explain that to colleges if need be. In fact, most of the applicants from Nepal apply to colleges in the US in their gap year. You can do a lot of cool stuff during gap year that you perhaps would not be able to do in high school because of time constraints. In fact, such activities will make your application stronger. If you do decide to take a gap year, use it meaningfully for your development and not just taking standardized tests and working on your college applications. Admissions officers won’t like that.
What’s more, it’s just September now. So I won’t say that its too late yet. Many colleges will accept January SAT scores. Try to find colleges that just need SAT and apply to them this year if possible. The whole process of applying to colleges is lengthy and demanding. So applying this year just to one/two colleges will at least make you familiar with the whole process. And there is always the chance of you being accepted depending on how much effort you put in. So good luck with whatever you end up deciding to do.
Read this blog post by Bhusan dai about gap year.