Alright, so I'm going to lay things out plainly because I am a year and a half into my physics undergrad at a CC, I am very likely to transfer to a good school in my state according to transfer counselors at both my CC and that college (It's a top 50 US school just fyi) and I also happen to have a GED. So here are some things that others told me what to do and what I actually ended up doing.
You don't need an associate's degree in anything to transfer to a 4 year school. You only need a sufficient amount of credits (45-60 typically) with good grades to make up for any high school record you have. If you have a 3.5+ GPA with 45 credits of work, especially in classes like calculus and physics, nobody cares what you did in high school, or even if you have a GED. An associate's looks ok, but it's not any different than 60 credits in your major to any of the schools I've applied to. Only some schools like University of Washington and UCSD have in their transfer pages that they sometimes prioritize Associate's holders, but they typically amend that with saying 2 years of coursework is equivalent.
So what do you do now? The first thing you need to do is take the placement test at your CC. They'll put you where you need to be math wise which is the most important thing you can do because you don't want to be thrown into calculus if your algebra and trig aren't up to speed. Take those prerequisites and study them like nothing else. If you place into precalc/trig, you should take an algebra based physics class as well to prepare you for the calculus level (Even if it's not required :D). This will be a good indicator of how you will like physics and basic lab work. This is what I did my first semester (Precalc/Trig/Algebra-based Physics), and I highly recommend it.
Every community college offers Calculus 1 and 2 that I've ever known. Many offer Calculus 3, Linear Algebra, and Differential Equations. And most offer Calculus Mechanics and Electricity/Magnetism. You should take ALL these classes that you can. Most 4-year schools within your state will accept them straight out and you'll save a ton of money. Check your school catalog to see what's offered.
You should be learning to program through all of this. If you haven't already read all the posts everywhere on the internet saying this, here it is now: If you can't program, then you can't do science. If you aren't comfortable learning on your own, sign up for some computer science courses at your CC. You'll probably start with Java, which will teach you the basics of how to program. Take Python or C for a start if you can though. This is what I did and again, highly recommended.
You should take some courses to meet the general education requirements as well. Two foreign language classes are usually advisable if you haven't had 4 years of it in high school. And take a writing course. Those are the big ones Universities look for. As for more, the rigor of the courses do matter. A university is less likely to accept you into their programs if you took mostly easy humanities courses, so don't go overboard with these kinds of classes. Stick to the classes relevant to your major if you have to pick between a Gen. Ed and a major course.
Next, if you do well in your math courses your first semester, try to get involved with the tutoring centers at your school. Every CC has them. You'll mainly be helping people with basic arithmetic and algebra. It may be stuff many of us can do in our heads, but for some people nothing is harder than adding fractions. You'll be paid pretty ok (I get 9.50/hr) so you can have some spending money. And if your boss is a professor, and they typically are, you can get a letter of recommendation out of it.
Next, you need to be that guy who talks to his/her professors. I don't mean brown nosing. You need to be interactive in class, respond to questions by your teacher, and do more than just the required problems for homework. If you have the same professor for two or more classes like I did, and they see you as a hard working and inquisitive student who goes above and beyond, they're likely to be more helpful. Don't throw your extra work in their face, but do hard problems, and ask questions about concepts that may not be covered in class. I've known people who got good letters of recommendation by doing these things, and have had two written for me in similar circumstances.
To sum it up, your fears are unwarranted. You'll be getting an inexpensive, early start to college. And it is significantly easier for someone with a 3.5+ GPA from a CC to get into a 4-year university than someone with a 3.5 out of high school. But the same rules apply. You have to work hard, go above and beyond, and make every class count. Don't feel like if you don't go to an Ivy like Stanford you won't make it as a physicist. The average GPA to transfer into a school like that is typically a 3.8-4.0. I know CMU is a 3.8 as a reference. So if you do that good and still don't get in, just keep going. If you've made it through your intro courses in physics and Calculus with A's, that's better than the bulk of people who take those classes at ANY four years school.
Study hard, get A's, surround yourself with like minded people, stay close with the people you love who believe in you, and make sure Physics is REALLY what you want. Do that, and a 4 year college won't be hard to get into.
EDIT: If you have a particular school in mind to transfer to in your state, they probably have a pdf dedicated to how your CC's classes transfer into their school, and what they look for in applicants. Talk to transfer counselors at both your CC and the university you want to transfer to.
