Ive been here in ireland a year now and i only studied spanish like one year and i still dont understand spanish. im still learning english too :(
Try going on Duolingo. It's a language-learning website and it starts from scratch so you'll be able to revise what you already know and learn new stuff along the way. You can also learn English too.
are you doing your junior cert?
you still have time.
junior cert dont really matters.
you can change to other subject in 4th year.