My friend and I are making sentences from English to Japanese.
We are trying to turn this sentence into Japanese:
I think he's 23 years old, I'm not sure however.
We came up with:
Omou kare wa 23sai. Wakarimasen dakedo.
Omou kare wa 23sai dakedo, wakarimasen.
Which of these sentences are grammatically correct? If both were wrong, what would be the correct way to say it in Japanese?