I am not sure if it always works this way, but if you start learning on modern board your learning curve could be much shorter - means that you need to learn to ride modern board anyway.
Like
you need to learn water start and gybing.
The older board could be easier to start with but I don't think that eventually save any time to reach this confidence level.
I did start with oldest crappy boards to progress to modern over years and I think from perspective that all this time was wasted.
If I did start on modern board I will do everything much quicker.
Save your time and learn on as modern 130L board as you could afford, IMO