"Should I attend Intermediate class even if I am not scoring very high in my practice sessions?"
The important thing is that you have the Basic structure down well. Periodically, read through pages 4 through 22 of your Viewer's Manual to refresh the structure in your mind. Also, be sure to spend some time analyzing your sessions after you do them, to see what you can learn. For example, did you mistake a big tree for a building? Or did you think that blue strip of paint was water? Or, did you fall off at a certain point and begin building castles? If so, where did that happen and why? If you are doing this and practicing faithfully, you'll be ready for Intermediate in November. Remember, at this point, it is not about accuracy. It is about learning the structure. "Site be damned! Structure is everything!" -- Ingo Swann.