35 y/o female concerned about hair loss - would a dermatologist be able to help? Which tests should I ask for?

I'm a 35 year old female with thinning hair and bald patches/receding hair line. I have had issues with thinning hair for years and then a widening part. It progressed to my temples. I had a baby 9 months ago. Now my hair line is receding to the point where the shape of my face looks different. My question is, who do I go and see for help wth this? My first thought is a dermatologist. Is that right? What tests should I ask my GP for prior, to make the most of any specialist appointments?