What's your professional opinion on 4-8 teeth extractions (getting braces) for my moderate crowding?

You have narrow "V" shaped arches with crowding and insufficient room for your tongue as well as only 6 tooth smile.You need Expansion Orthopedics not contraction orthodontics.  Treatment plans than contract your arch can set off TMJ issues, headaches or migrainesThis will also improve yoyur nasal pharyngeal airweaywith many health benefits.

You absolutely, positively do NOT want to extract any bicuspid teeth. If you choose this course of treatment you will permanently alter the shape of your face, you will permanently compromise your airway and TMJ's and will end up with a very narrow smile.If you try to straighten your teeth without changing the size of your dental arches you will have excessive flaring of the teeth.Your best bet is to enlarge your dental arches BEFORE straightening your teeth. Many doctors will tell you this is not possible because you are no longer growing. This is NOT true as we enlarge adult dental arches every single day in our practice; as do 1,000's of other doctors. Find a doctor who understands "adult arch development" and you will end up with a healthier airway, healthier TMJ's and a broader more beautiful smile while maintaining your beautiful face.Good luck!

Even if extraction of premolars is the best option, the extractions can always be done later.  Once done, there is no going back.  I would see how things go with expansion and braces, and if it isn't enough, consider extractions.  In my opinion though, extractions aren't likely needed and would personally avoid them.