https://www.wileyski.com/product/ho-syndicate-a3-waterski-2014-66/
Okay so I know that this goes against what I commented above, but here's a good deal on (from what I understand) a good course ski. Will be less forgiving than a Senate/Omni and require a little more work across the wakes because of the smaller width, but it's the right price and I've seen people learn the course on various levels of skis. If you would rather get the Senate/Omni, wait until the end of the summer when people are buying new stuff and hit up Ski It Again.
Also, now that I think about it, D3 Quest or X7 are also good skis to learn on. Or an ARC if you can find one for the right price. D3 is a forgiving ski brand in general.
66"-67" is going to be your fit.
Sorry for rambling lol