Hey Debbie, welcome!
As the owner of both a gas and diesel MBZ, I can tell you they are quite different. It takes a couple of minutes to adjust driving styles(pedal pressure) when switching between the two.
My diesel was the long distance commuter vehicle and it's hard to beat for freeway cruising. The price of diesel in LA is about the price of regular unleaded so that's kind of a wash. The main issue with diesel is availability where I live and that may not be a problem for you.
I love my 300D, but I would only drive the turbo. It adds loads to the driving pleasure of the diesel but doesn't make it race-worthy
. I'm not sure I would recommend my car for day to day street driving for a lady since it can feel quite heavy. But one thing is for sure, this car is made to withstand accidents and you would be safer by simply surviving an accident with a less dense vehicle!
To check out this car, there's no subsitute for a mechanic performing tests, compression etc. Looking for subtle signs the car has been cared for is important. Examples are the condition of the foot pedals, rubber seals around the doors, missing knobs etc. Basically you're looking for pride of ownership.
Best wishes, let us know what you decide!