The first thing to do is to continue to do very well in high school. It sounds like you are already doing this.
The second thing to do is to figure out what your budget is. You probably cannot and very definitely should not borrow the full cost of attending UCLA as an out of state (or international) student. Four years at $65,000 per year adds up to way too much debt.
You also should realize that getting a degree from a university in the US does not allow you to stay in the US to work. International students in the US are expected to return to their home country after graduation. This is in contrast to some other countries (Canada is the example I am most familiar with) that will allow graduates from their universities to get a work permit to stay.
There are two ways for an international student to study in the US (or Canada, Australia, the UK, …). One way is to attend a university in your home country, and then come here for one semester or for one academic year as an exchange student. The other way is to apply to and attend a university in the US for a full four years and graduate from a university here.
Also, as others have said there are thousands of universities and colleges in the US. Picking a small handful to apply to can be a challenge just by itself. Knowing that you want to study engineering does narrow down the choice, but still leaves a lot of options.