On a physical level, it needs:
Flexibility
Strength
Mobility

If either of these 3 are absent or even if 1 one of them is absent.
It will be really frustrating as a beginner.

But who can even reach the top without stepping on initial steps? Right!

So, even if you lack these things, just give it a start. And maybe you can achieve it in just a few weeks or it could take months as well. Depends on persons' body.

And, at the spiritual level Youga is tough. Though it is not impossible, but yes, it us tough.

I mean caring for self, loving yourself, and things like these are rarely talked in our society.
Yoga akso needs self-discipline and continuous practice to bring the kind of result you aspire.
And, it is a time taking process
But "Rome was not built in a Day" and just like that, you can't become Yogi in a Day.

It takes Years and Years to become good.

Not Impossible, but yes Yoga is tough.