I personally think that the idea of buying a snake that doesn't grow very big for a beginner is false logic because if you buy a hatchy, by the time that it gets any real size you won't be a beginner anymore, you'll have a year or so under your belt by that stage. (Olives are excluded from this)
So disregarding the idea of a smaller growing snake as it's a mute point, it really comes down to two things as far as I'm concerned.
The level of care required for the snake. ie you don't want to worry about humidity or any over the top straight up.
Fortunately most australian pythons are very easy to take care of, however there would be a few I'd recommend to wait for a while.
Green Tree Python,Water python and as I said olive as they do grow fairly big fairly quickly.
So the big question that needs answering is which snake is most likely going to have a nice temperament.
I'll start by saying that all snakes like most other animals have individual personalities.
So there is no absolute answer, however some species must just be genetically inclined to be more relaxed and less food responsive and other species the exact opposite. There are exceptions to every rule however these are in my opinion some to avoid and some to look into.
Stay clear of Jungle pythons, Scrub pythons,olive pythons and green tree pythons as they can tend to be a little bitchy at times.
Some of the above also have genetic traits line bred into them that put simply means they are literally retarded them to the point of having a high chance of being an aggressive animal.
My choice would be a bredli as they can be absolute puppy dogs and handle brilliantly. I've had a bredli for over a year now from a hatchy and have literally never been bitten or struck at by this snake and it has never had any issues feeding.
As far as I'm concerned bredli is really the only one that sticks out as being overly puppy like and many many people report the same traits.
That being said any Anterasia or woma would be your best bet after a bredli in my opinion.
I have a spotted for a while till I gave it away to a member on here when I was moving and it had a strong food response and would latch on 50% of the time I went to handle her. She was a little flighty aswell when out and didn't like any fast movements. That's my personal experience I've also got a close friend who has a spotted that's a total bub so it really comes down to the specific snake you end up with.
Something I'd also like to make you aware of for you and your future snake/s sake.
There will be some people that may have many years of reptile husbandry under their belt however are full of stupid ideas and incorrect facts. Yes it's true that you'll only learn with time however if your vacuous to begin with it doesn't matter how long your given your always going to be stupid and full of false information, that coupled with speaking with authority is a dangerous combination.
So just be aware that just because someone on a forum tells your something don't take it 100%, take it as a guide and go find some facts to back up what they are saying.
That being said, there are some very intelligent and wise members full of wisdom on forums that will provide you with the best information you'll get anywhere, kidna like reptile Yoda's if you will
Stupid people are everywhere, just be aware of this.
Have fun choosing which snake to buy
This post was really helpful, thank you!