Trust yourself rather than trusting what others say... "Good attempt" is a vague term unless its YOU who is attempting the paper...Most aspirants almost always say their attempt was good but you never know...

Trust your knowledge, skills and taste for the subject - If all these add up to the word "YES", then go for it. There does exist the element of risk e.g. the paper setter might ask you to solve a simple F=ma relationship or challenge you with an enough complicated question to award you zero -

Go through the past papers - They will tell you that the difficulty level has never been at the extremes - too easy or too hard- There always has been a region where you can score fairly e.g. 60-80, and i dont think that is in any way bad.

The bottom line i would suggest is - Do not leave out too many topics or chapters in choice..This can be hurting..