I did GCSE astronomy, got half marks in the exam and got an F. Teacher told me GCSE astronomy is super difficult because of the crazy high grade boundaries cause adults do GCSE astronomy for fun in their spare time or something? Idk basically that sucked
I think it's super interesting--the wider Universe is kind of like the laboratory we wish we could have on Earth, because that's where all the interesting theoretical stuff plays out on massive scales (dark matter, black holes, etc.).
To get a PhD and then, especially, to stay in the field as a researcher is quite competitive. However, if you set your mind to it and try to get as much experience as possible during your undergrad, then you're well-placed for success! If you want to see what it's like as a researcher, check out this link: https://imagine.gsfc.nasa.gov/ask_astro/profession.html
If you want any more information, please let me know!