Keep or return?

[None !IGORsW/P/E No.14771965]

Hey fa, so I ordered this coat https://www.uniqlo.com/ca/en/products/E419982-000?colorCode=COL09

in size Medium because the Large I tried before was too long in the sleeves and in the feedback everyone said this coat runs too big. So I ordered this coat in Medium (I wear shirts size Medium). So now I'm not sure if this coat too small on me? It fits like really "slim fit"... Look where the shoulder seams are. And look post for comparison at the size M uniqlo turtleneck - it's perfect in size M, drop shoulders, roomy.