Welcome aboard!! This is a great place to ask such questions. While very cheap
, a Snark might not last too many seasons. If you can find a cheap
Sunfish ($350) it might be a better value in the long run. Many parts
are available through eBay.
The question about height is not near so important as weight and agility. If you are young and bendable then you can sail even smaller boats effectively. While younger I had a great deal of fun sailing an 8' Sabot and I'm 6' 2" and weighed in then at about 175.