Your sentence isn't natural, and most similar sentences don't seem very natural to me either. ", etc. It's common for the present perfect to follow "now" when the sense is "now (that)" -- as in "Now (that) I've figured it out, I'll explain it to you" -- but this is structurally different from your example.
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Mister Micawber
Perhaps in AmE it is more frequent, as it seems natural enough to me-- in many cases when an action is just completed.
Now I've learnt it; now I've achieved my goal; now I've finished the project, etc.
AnonymousCan we use the present perfect tense with the word now? I would really appreciate your inputs.
After what you have explained, now I have learned its usage.
(in the sense that "After what you have explained, now I know its usage.)
Most certainly you can, though your particular example is not idiom