"there's no telling what I can do. "?

[Jenny Lau]

I don't know the meaning of this sentence
"there's no telling what I can do." Is that mean there's nothing I can't do?
Here is the context: It took two more years, but I earned my black belt. That night our family went out to celebrate. "You should wear your black belt,"Alec said. I'd never felt so proud.I've lost 50 pounds since starting Tae Kwan Do, but that's not what makes me happiest. It's knowing I could reach for an impossible goal, work for it with all my strength and achieve it. Now I think there's no telling what I can do.

 

[David L.]

'there is no telling' is an idiom used to convey the impossibility of knowing what has happened, or will happen : 'There's no telling how she will react.'

In your example, it means that having achieved what he has, having proved what he is capable of doing so far, then it seems like the possibilities for what else he might now go on to achieve feel limitless...who knows? It seems so wide open, it's impossible to predict - it could be anything!!

You will understand, this sentiment is born of an expansive emotional state and not necessarily reality!

 

[Jenny Lau]

Thank you! Your answer is so clear.