Uhm, of course, why wouldn't it be??
A lot of people have done an undergrad outside the US and then a masters in the US.
But you're literally so far ahead it's pretty pointless/crazy.
After your undergrad you're ideally looking for 3-5 years work experience/activities before doing a masters because US universities place a lot of value on that as they want students who basically got their hands dirty in real life already as oppose to just being a good book-smart student.
(Unless maybe you want do do theoretical physics)...
But you're literally making plans for something thats probably
7-8 years from now...There is
so much that will happen until then.
I wouldn't personally think about it too much other than in brief detail.
Just make sure you can get as good of an undergrad degree as possible and do a lot of activities (Unis know that you're most likely doing it to be a more attractive candidate rather than out of passion per se and that's perfectly fine, what's the difference?).
But make sure to enjoy life a bit as well, undergrad years are supposed to be the best years of your life lol, you're only young once... and there's other things than simply increasing your employability/acceptance rate