This does not seem to make much sense as an expression (unless it is very literal, as in just about to start a marathon). Does it indicate being 'stuck' at the beginning of sth?
It must refer to something known from the context. Imagine that you're on the phone: "So, you see the queue already? I am standing at the beginning".
I think this is a situation where "start" is much more likely than "beginning" in English.