Hi! I'm currently a year 11 and I do Latin and History. Latin is definitely very difficult, but it might be more so at my school because Latin is taught as a twilight subject. I would say Latin has definitely developed my analytical skills! My friends do geography and I've heard it's definitely less difficult than history, but at times it is also boring. My advice is definitely to look at past papers and figure out which topic you're doing, and whether or not they're interesting. I would say that some of the skills you learn in Latin are definitely specific to Latin, whereas the skills you learn in geography overlap with the other humanities and sciences. Personally, I would opt for Latin, especially because language skills are always appreciated, and it's also difficult to teach yourself Latin, whereas geography is easily learnt in a book.
From my friends who do PE: PE has a lot of overlap with Biology, and playing sports is always appreciated by employers etc.
Don't worry too much, GCSEs aren't the end of the world!