Hi to you, Ive climbed at altitude, Kilimanjaro just over 6000 m, like the others have said get some acclimatisation in first if its possible, take some Diamox tablets with you for altitude sickness but be careful they do dehydrate you so drink plenty, and go with how your body's feeling. you will feel very weak and have no energy, but fight it, just carry on, you will be surprised what your body can do at altitude. your breathing rate will increase, so practise deep breathing exercisers to open your lungs up. i wish you all the best.