should i take more lessons
Since these guys all started talking about their adventures and the dangers of starting off in surf, I''ll stick to your question:
The basic class was plenty for you to go out and practice the principles you''ve learned. What you need now is not another class; it''s hours with your hand on the tiller. Experience will be your best teacher now.
You show good sense in wanting to stay within sight (swimming distance, among other traffic who may be able to assist you, etc.) of land. That''s very prudent. The biggest variable in open water in a small daysailer will be tide, swell size, surface chop (the little wind-waves), and of course windspeed (oh, and motor-boaters: your biggest hazard). Try to choose a day with relatively flat water and light-to-moderate wind, so that you can concentrate on honing your skill and not battling for survival during a very wet ride. What you want now is a reasonable window for skill development.
In a small daysailor like that, I''d make sure I was wearing at least a partial wetsuit: hypothermia will set in quickly, causing you to shake, tire quickly, and a fog over your judgment.
You must assume that you WILL tip it over repeatedly, you WILL be soaked to the bone, and that you WILL lose everything overboard that you haven''t strapped down. But that''s the fun of learning. Go for it! And when you get tired of getting so wet, you can buy a trailer-sailer with a swing-keel. . .