Color: Too light
Fabric: Sharkskin - shiny, casual, bit of a sleeze factor
Cut: Too tight
Shirt: Too purple
You refer to 'fashion knowledge' --
This is not about fashion. Let me repeat for clarity and emphasis: Fashion is not what you want. You also do not want: stylish, popular, up to date, modern, timely, trendy, current, hip, young, happening, different, unique, European, or whatever other adjective the hourly-wage sales associate tries to convince you you want. If you're not sure, ask the sales associate if you could wear the suit & shirt combo out for drinks after work. If he/she says "Yes - sure!" then it's the wrong suit. (The right answer would be "This? Not if you want any action.")
For your interview, you do not want the kind of suit that looks like something a stylish 20-something would wear. That's completely the wrong look. Medical schools do not want stylish 20-somethings. They do not want someone who breaks the 'conventional interview attire' rules because that indicates someone who will break other rules before they have the judgement or accumulated experience to know when it's OK to bend the rules.
You do want the kind of suit an affluent 40-something would wear. Something serious, conservative, solid -- yes boring. This is the suit you want for your medical school interview. Navy blue or grey, possibly with a subtle stripe. That's it. Not black. Not brown. Not plaid. Navy blue or grey, possibly with a subtle stripe -- that's the interview uniform.