This is a UK-based site, so some people here might not be familiar with US 'grades'. For those who need a translation, US '7th grade' = UK 'Year 8', which most people here will remember as he '2nd Year of secondary school', using the older way of doing things. (i.e. it refers to young people who're 12 years old at the start of the academic year, and who will have their 13th birthday during that year).
If you were emailing love letters to a girl a couple of years ago, Goku_San, you're remarkably advanced for your age. Most boys would do anything to avoid girls at that age! Even though girls tend to be more 'advanced' in their feelings at around your age, it would be unwise to assume that the girl you're referring to feels the same way as you do. Just enjoy having her as your friend (while trying to avoid any feelings of animosity towards other boys who might also want to be friends with her) and see what develops. Six years is a long time!