My 10cents worth:
I'm a 1.6m short lady and I ride a 27.5" size SMALL. I've owned a 26er, 27.5, and 29er. My thoughts on the different wheel sizes:
26er - great starting wheel size for beginner MTBers. Can get a little sketch when you get into more technical riding
27.5 - This is my happy place. It's faster rolling than the 26er but not as exhausting to get going as the 29er. Nimble around corners and super fun on the technical terrain.
29er - Felt like a bus. Always felt completely wiped after a ride on single track. Getting that thing to turn was ugh. Handling just never felt great.
