Learned to sail (and dated my future wife and Admiral) on a Moth - like the one design Butterfly.
Then I learned to optimize my sailing in the Key West Naval Sailing Association on a Sunfish, racing monthly against 30 other 20 somethings. I have sailed solo sailed a Sunfish on vacation for the last 50 summers in the Thousand Islands of New York. If I knew a racing fleet of Sunfish on Lake Erie, I might recommend 2 years in such a fleet before moving up to the Vic 18. But I know of no such Sunfish fleet. Erie, PA would be the place for one if it existed. But I hav cruised there several times, a never seen a fleet of Sunfish. No faster way to learn how to trim a sail, and control heel.
But the Admiral and I sailed a Rhodes 19 in Narragansett Bay when I was at Navy OCS. What fun! Not as intense a learning experience, but still really good, and fun with a crew of one or two. The Vic 18 sounds like the Rhodes 19, so I that would be my choice. And do take a keel, cruising boat sailing class wherever you can. On the Vic 18, you could even "camp" overnight at the Erie State Park Bay off the NW corner of Erie Bay. A beautiful place, one of the best on Lake Erie! Go here for lunch on the hook of you are not yet up for an overnight.
Then, someday, you can upgrade to a great cruising boat like our '77 h27!
Fair winds, and following seas.