Rakesh: What you're saying is absolutely correct. When you're playing, you're a musician and not a guitarist or a drummer or anything other than a musician. You incorporate everything into your playing and strumming should totally be based on the beat/rhythm.
That being said, I didn't like your strumming because it seems (to me) that it changes the entire mood of the song. Also, I'd advise you to use more open chords when you're playing with just a guitar and nothing else. The ring of the open strings gives you a nicer sound overall and doesn't let the song feel empty. You have a nice voice. You're certainly on the right track though and I think your strumming will improve with time.
Also, don't just dismiss what other people are saying without looking carefully.
And surely you’ll buy your pint cup !
and surely I’ll buy mine !
And we'll take a cup o’ kindness yet,
for auld lang syne.