Coming out

So I’ve always known for as long as I can remember I’m bi maybe more into females i don’t make a big thing about it or whatever, I’ve had a few dates some kisses etc. But one of my main things is no one really knows my mum doesn’t and every time I bring up the subject of being a lesbian or being bi she says ‘oh well I’d rather you be normal’ and I don’t really know what to do I’ve always been raised on that and it’s sometimes difficult because I can’t be in a relationship with a girl without the fear of my mum not approving and not being okay with it. I’m 17 btw