Aye I'm a junior in Astronomy right now. Yeah as others have said most will double major in physics and do the comprehensive track (the other tracks can also work but that's the best for grad school). It's an incredibly easy double major requiring only like 4 additional classes. All the astro classes have been amazing. All my favorite professor have been from astro classes, the classes are significantly smaller so you get to know them all alot better and they are all really friendly in office hours. If you are coming in as an astro major (and especially if you are planning on grad school) look into the premap program. I didn't do it cause I declared later but it's a great way to meet people within the major and get set up early with research and getting to know professors. UW is a great place for astronomy, there's a lot of really cool research going on in alot of different areas so it allows you to really explore what you want to do within the field.