Pilates Novice

Just had my first Pilates class and wow! I am SO unflexible in my hamstrings! The instructor was holding back the laughter as my legs were shaking and definitely no where near the 90 degree angle with the rest of my body! This is hard stuff, but even walking out of there I felt where my muscles had been worked and I like that! I'm so looking forward to being stronger overall and having flexibility. I'm including a picture of what I'm supposed to be able to do...looks easy, but you try holding your legs out completely straight at that angle and see how long you can hold it! Good luck!