It's fine.

I'm really happy to help if I can. And...yay for learning Japanese~
Um...Japanese has kind of a complex system of honorifics. You don't need to worry about it now if you don't want to, but...for now, it's important that you remember that there's two words for every relative. There's one word for your own relatives (that is more humble) and one word that you use for other people's relatives (that is more formal). So...
Haha - my mother (yes, it's really 'haha'.

It's an easy one to remember)
Okaasan - another person's mother (it can also sometimes be used by younger kids to refer to their own mother. But it sounds kind of childish if you do that as an adult)
Ane - my big sister
Oneesan - another person's big sister (ditto on kids sometimes using it for their own big sisters.

Also, it doubles as a term for an older girl that a kid looks up to. You'll often hear 'oneesan' when there's no real blood ties, but just a bond of friendship. The same with 'oniisan', but for boys)
Imouto - my little sister
Imoutosan - another person's little sister