The theme is to stop procrastinating or making up excuses and steady talking about something you're gonna do or wanna do, and just do it. A shorter theme can also be: actions speak louder than words.<span />
A theme of this poem is to take advantage of opportunities in the world and to avoid excuses and them getting in the way of you seizing these opportunities. This theme fits the poem because the character in the poem is doing absolutely everything that they can and wasting a large amount of time making excuses, instead of just seizing the moment and taking a chance and diving. Hope this helps!
I think sentence (4) Since they spent time making sure the gardens were as nice as the rest of the piece, we can assume that the Taj Mahal was always meant to be art.