I think it's great that your daughter is traveling. I only saw the Alps from a plane, but they looked amazing. I live in Colorado and frequently hike in the mountains. At 7000ft you do start to get out of breath a bit easier but I've done two 14ers (mountains that are above 14,000 ft) and I was fine. I think it's different for everyone. Depends on how much exercise you have normally, what your normal lung function is, etc. I recommend taking Tylenol or something similar before hand (in case of headache) and drink lots of water! Always have water with you and tell her not to feel bad if she needs to take it slow!