I don't think you need extractions at all. Def get several opinions...
In those pictures, it actually looks like you are a candidate for Invisalign, but again hard to tell for sure.
I personally prefer braces over Invisalign just to save some money and ensure I am going to get the exact results or close to it that I am looking for.
Invisalign is awesome though and there are some dentist/orthodontist that are really great at it.
Braced Twice. Wear Your Retainers!
Ceramic Braces On Top and Metal Braces On Bottom, Palatal Expander - First Time Around
Metal braces top and bottom - Second Time
Now Wearing Retainers At Night!