Some general comments:
Start reading and gathering resources now. The more you read and the more good resources you use, you'll start to see what's best for you and your child.
Costs are usually just what the college is required to say are necessary costs, which include tuition, room, board, and required fees. Depending on the source you look at, there might also be budgets for books, personal expenses, and transportation. In my experience, they ignore or exclude health insurance, college visits, computer/technology, and the smaller things like ACT/SAT, application fees, housing deposits, etc.
Roughly/broadly/generally speaking, private has a higher sticker cost than public, and in-state will usually be cheaper than out-of-state. As noted above, private will tend to offer scholarships that discount their costs greatly, but so far in my experience still not enough to be comparable to in-state public.
I echo the strategy to find schools where your child is in the top 50%, although I would go further and say top 25%. Take your child's SAT scores and GPA and go hunting. You can find these schools pretty easily by those two metrics, as all schools publish that data. My son is in the top 25% of his class at a private out of state school, and they gave him scholarships which knocked about 1/3 of the price off.
Each college is required to have an net price calculator. I have read, and my experience confirms, that these are generally very close to realistic assuming you put in the correct data that they ask for. Here's an example of one:
https://utulsa.studentaidcalculator.com/survey.aspxLots of young people love biology as a subject and a major, especially young women. However, it is not very marketable as a degree from what I have seen. If your child chooses evolutionary biology, they will very likely need to go to graduate school in order to get a decent-paying job. If they do not go to graduate school, they might get a job, and it might pay just a bit more than a job at the local fast food joint. That's my opinion - have your child research and prove me wrong. (I doubt they can.) Research this now so your child can make an informed decision rather than get the degree and end up with a $25K job and $75K in student loans.
Having a good idea of what majors they're interested in does help quite a bit in the college search and application process. My middle son wasn't sure between Mechanical Engineering or Chemical Engineering, so we just looked at schools that had both. I've actually known people who started at schools and then had to transfer because the majors they wanted were not at the schools they started at.
If your child goes to a school that uses FAFSA only, it will depend on whom they live with most (365/2+1 overnights) in the 12 months ending on the day they complete the FAFSA. If you and the other parent are no longer married and they live with you, then it will be your assets and income listed on the FAFSA; the other parent's data is not collected and will not impact FAFSA aid. FAFSA opens on 10/1 every year; applying as early as possible can help, because schools give out aid until it's gone, and some schools run out. So if your child is a senior now, you can apply for FAFSA aid for their freshman year about three weeks from tomorrow.
FAFSA income is based on prior prior, so if your child is a senior in high school now, it will be your income from 2019 that will be used for their freshman year.
On early admission stuff, be sure to read to see if it's binding or not and consider that when applying. Most often, if it is binding and the school does not offer enough aid to make it financially viable, you're still expected to be on the hook. I don't like them having that power over me, so I discouraged that with my kids.
Ditto what someone said about Questbridge. It's for first-generation college kids who are Ivy League potentials. I think they also have a fair amount of binding-ness to their process, which again is a turnoff for me. Doesn't sound like it applies to your child.
Totally OK to have her 529 listed with you as the owner. Actually, for FAFSA I'm fairly certain it doesn't matter - 529's are considered parental assets regardless of whether they're owned by the student or the parent.
There is a whole 'nother aid system called CSS that has very different rules from FAFSA, mostly used by high-end liberal arts colleges, as well as some of the competitive universities. Most CSS schools expect contributions from both parents even if they are divorced.
Ditto what someone else said about being a big fish in a small pond. It's a Gladwell book, I think David vs. Goliath, and the argument is backed up by data that it is better to be a big fish in a small pond rather than the reverse. Colleges will try to get you to believe the reverse is true; I don't buy it.