I believe everyone should make their first few stocks from the blank so they can truly understand what is going on and to appreciate the art.
I also overwhelmingly prefer English walnut. Yes, you can get great working Claro and rough working English, but the odds are overwhelmingly that the scenario will be the opposite.
Also, I think if you work on a more expensive blank you take more time and think through each cut before you make it, leading to an even better understanding of what exactly is going on.
Of course all of this is just my opinion and just food for thought. The main thing is that I applaud you for taking the plunge and hope it sparks a fire in you that never goes out! Please see the project through to the end and do not hessitate to ask questions if you get stuck.