You a certainly not too old for Invisalign. I have treated patients in their fourties and fifties with this.
Anatomically the support of the teeth does not change and this is why age is irrelevant.
Obviously the earlier the teeth are treated, the longer the patient will have straight teeth and the longer that person can benefit from it which is why the majority of treatment is done in the teenage years.
The best course of action is to see an Invisalign experienced practitioner and take his/her advice about what the ideal treatment for you would be.
Kind regards
Dr Kailesh Solanki
Kissdental
157 Woodsend Road, Flixton, Manchester, M41 8GN
Web: www.kissdental.co.uk Tel: 0161 748 5250