speaking as someone who has a degree and spent a year at grad school for a degree, a few insights on how the astronomy gig works.
First, there is no really wrong field to study in. Astronomy is a mixing pot of all the sciences, and the programs reflect that. You can get into the graduate programs with anything from a straight astronomy degree, to mathematics and engineering. As it is, it's good that you like a large variety of physics fields, as the astronomy programs are even more 'jack of all trades' than a regular physics program (which is 'jack of all trades' compared to engineering...).
So the big question is: Do you intend to go for a Ph.D.? I'd say masters but in physics the difference is usually in the research and publishing of a thesis. You have to pass the same classes to nearly the same degree for both the Ph.D. and masters.
If you do, you don't have to worry about a good astronomy program specifically. You can also find a good physics program with a field you like (quantum, particle physics etc) if it's more convenient cost & Location wise.
Keep up with the math, especially differential equations.
Any computer courses are also a big help and highly attractive to grad schools and employers. Computer programming is a key skill in modern research.
If you don't want to get at Ph.D. and want a real taste of astronomy, I do recommend finding a college with a dedicated degree track for it. A key factor is also the universities access to real research grade telescopes. Try to dig up if your prospective campus' are affiliated with large telescopes (Univ. of California system gets regular time on Keck!). While you may not get any real time on them yourself, you may get lucky and get to be a grad students flunky! At the very least you'll know the campus is serious about it's program.
Another tip is to look up campuses that have an active astronomy R.E.U (research experience for undergrads). These are programs where selected undergrads get a taste of the field and get to be paid interns for a summer. You do a real, if simple and abbreviated, research project and are almost always given some hands on experience at a live scope. Finding a campus like this has two benefits: You'll know they're serious about the program, and you'll have a foot in the door when applying for the internship!
Now, for a reality check if you're thinking of going professional astronomer: the competition is insanely steep. There are ~5,000 paid positions worldwide (I think, even if that's wrong, the number is small!) The US produces hundreds of astronomy ph.d.'s every year, and even fewer positions open up. So you've got a LOT of competition.
This doesn't mean you don't have a chance, but it does mean you've got to work for it. Good news is you'll have a physics degree (astronomy is usually just tacked on) so you'll still have a good shot at a good job. But it may not be the research astronomer/professor position you're thinking about. Example: One of my grad student friends went on to work with a company making Doppler weather radars, leveraging his knowledge of studying Nebulae into helping with cloud observations.