Does the head-gasket in 2009 Volvo C30 need replacement?

[C30Vehicle]

Does the smell of combustion in coolant fluid usually indicate that the head-gasket needs replacement - or what are other reasons for why the smell of combustion shows-up in coolant fluid?

My 2009 Volvo C30 has 90,000 miles. The coolant level dropped quickly from the 'MAX' fluid level even during minimal use of the car - yet the engine running temperature remained at normal during one brief 5 to 10 minute road test at around 50 mph. After the 5 to 10 minutes of travel, the coolant level was below the 'MIN' mark.

My mechanic mentioned that 90,000 miles on a Volvo C30 is normally too early for head-gasket replacement. I was told that the engine head-gaskets are considered for replacement if the vehicle has previously overheated.