lake Can a 15 year old (me) fly domestically within the US by themselves?

Ok, I might be flying to Oklahoma from Alabama by myself, so with no help. I've flown alot so I know how it works and all. My mum was looking up prices online and it said a 15 year old can't fly alone but when we asked a delta person one time they sai you can sometimes or something....So can I fly alone? Plus it's only domestic.there