I'm a Republican, but I can't help admire the Queen.

On the 21st of April, Queen Elizabeth II turned 90 years old.

By the ripe old age 90, most people are – at the very least – retired. Many are incapable of taking care of themselves. Those who can are getting stuck into gardening, or else cuddled up with a good book.

Not our Liz.

She’s rampaging around the country, meeting visiting dignitaries, tasting people’s cakes and reading letters from her fans.

She’s been doing her job for 63 years, and she’s showing no signs of slowing down.

I’ve always been a vocal advocate of Australia’s Republican movement. I see the continued involvement of Britain in Australia as archaic and outdated. Queen Elizabeth, in her position as Australia’s monarch, means nothing to me.

But damn. You have to admire that work ethic.

It’s no picnic, either, being the Queen. Her Highness Queen Elizabeth does 430 engagements a year, often travelling to different parts of the country for day-trips.

She has a weekly meeting with the Prime Minister (6.30 on a Wednesday, in case you were thinking of popping in).

She often visits up to three venues before lunch, which seems sort of like overkill, and dedicates hours of the morning to “audiences” with officials and the general public.

If you’re thinking that all sounds a bit doddery-old-lady rather than impressive-boss-of-the-Commonwealth, you’d be wrong. Last week, Prince William confirmed his dear old Granny is still “very much the boss” – and if Will says it, it must be true.

And Liz’s popularity shows no sign of waning, with 70 percent of the British public in favour of her reigning “as long as possible”.

Let’s stop for a second and let that one sink in: Australia can’t keep the same Prime Minister around for more than a year, and ol’ Liz is 63 years down and still the crowd favourite.

As far as I’m concerned, there’s no reason for Australia to remain part of the Commonwealth. The necessity for such ties is gone, and any lingering nostalgia towards the “motherland” is fading fast. I don’t think Queen Elizabeth II, or any of her royal disciples, have a place in our nation.

But boy, do I admire her staying power.

Click through the gallery to see Queen Elizabeth throughout the years.