Can I opt for invisalign treatment? Just front 6 teeth need to be straighten up for better smile (Photos)

yes, you can go with Invisalign treatment. you will get very fast results with Invisalign as compared to braces in crowding [your case] case.

Yes you can opt for Invisalign to correct your crowding. Without seeing the overall health of your teeth and your bite, it is difficult for me to comment on the duration of the treatment but Invisalign seems to be a good option. 
I have treated many such cases with great results with Invisalign. 
Hope this helps.
Best wishes. 

You will need to treat more than just the front six teeth, but Invisalign can be used to help you.

Yes, you can try invisalign braces if your teeth is weak then I agree with your dentist that choosing orthodontics treatment is not a good idea. 

HI There,  I am a cosmetically trained dentist. We LOVE Invisalign therapy for creating beautiful, healthy and natural smiles.  You will be sooooo glad you invested in yourself this way!!! Look on line and call a few offices until you find the practitioner that resonates best with you with the cost you want. I only have two addition to your inquiry:
1.   Invisalign treatment will treat all your teeth - make them all better along with giving your smile the best harmony in your face.  You want to think broadly about your whole smile.  You will have the best result coming from that place, rather than fixing just the front six teeth.  
2.  Ask that your arches be expanded.  Do not have any teeth removed.  Search until you find a dentist who can give you this.  
Have fun!  It is amazing to watch your new smile emerge as your teeth straighten!