Skiing at 12 weeks

I have a ski trip planned for February. I'll be 12 weeks. Is it ok to ski? Everything I've read has said that the baby is tucked under the pubic bone and protected. I'm also going to a place at a high altitude (11,000 feet) from living in a low one (700 feet). Any concerns to worry about with altitude? I haven't been to the doctor yet but the nurse on the office helpline didn't seem concerned about either issue. Thoughts?