My recommendations would depend on several things:
1...What grade are you in?
2...How much math and physics have you had?
3...What kind of topic in astronomy interests you the most?
4...Are you after a science fair project that will win the Westinghouse
Science Talent Search, or would you settle for
5...How much money and time do you want to invest?
6...Do you need a mentor to help you?
7...Do you want to collect new data, or use data already available, say, on the
Internet?
Your answer to all of these questions will help narrow the possibilities
and make the recommendations I could give you, meaningful to your personal
needs and circumstances!