Many English speakers do not differentiate between the two and use "will" for the simple future even for "I" and "we".
They used to be differentiated? Woah. Learn something new every day, I suppose.
I know! I feel like I've learned as much about English as I have about Esperanto completing these lessons. I guess that's what happens growing up in the US - we don't always speaks the goodest grammars ;)