yes...you will be fine attending school with your exams as proof that you've finished your high school education. if you enroll in a community college, you will have to sit for their standard placement testing, to determine what level math and english classes you will be enrolled in. more amusingly, you also will most likely have to do some testing at the foreign student's office, to prove that you are a proficient english speaker. (anthony said to the girl, "Um...you've heard of ENGLAND, right?" as in, "We invented the language, you numskull!"

)
if you enroll at the university level first, you will be required to sit for the ACT or SAT test, depending on the individual university's requirements.
as far as financial aid goes, Rebeccajo is right...you are not a conditional permanent resident at this point. you are an adjustment applicant. you are, however, an "eligible non-citizen". the way that we got anthony qualified for federal financial aid was by producing his Advance Parole, as Parolees DO qualify for Pell Grants! of course, it took some wrangling and convincing talk to get the financial aid officers at the school to actually believe us!
QUOTE
You must be one of the following to receive federal
student aid:
• U.S. citizen
• U.S. national (includes natives of American
Samoa or Swain’s Island)
• U.S. permanent resident who has an I-151,
I-551, or I-551C (Permanent Resident Card)
If you’re not in one of these categories, you must have
an Arrival-Departure Record (I-94) from U.S. Citizenship
and Immigration Services (USCIS) showing one of the
following designations:
• “Refugee”
• “Asylum Granted”
• “Cuban-Haitian Entrant, Status Pending”
• “Conditional Entrant” (valid only if issued
before April 1, 1980)
• “Parolee” (You must be paroled into the United States
for at least one year and you must be able to provide evi-
dence from the USCIS that you are in the United States
for other than a temporary purpose and that you intend
to become a U.S. citizen or permanent resident.)
If you have only a Notice of Approval to Apply for Permanent
Residence (I-171 or I-464), you’re not eligible for federal student
financial aid.
If you’re in the United States on certain visas, including an F1
or F2 student visa, or a J1 or J2 exchange visitor visa, you’re not
eligible for federal student financial aid.
now, what happened to us, however, was that the first year following anthony's application for AOS, he was approved...however, there is a provision in the law that says that you are only eligible for financial aid during the first year of parolee status, because they expect that an application for AOS should be approved and you should have the greencard in hand by that time. in our case, sadly, that was not so.
receipt of federal funds for financial aid is not prohibited, and does not count as "public aid".
good luck to you, and i wish you all the best!