How far can an inexperienced kayaker paddle in a day?

My daughter is 13 and is new to kayaking. I'm also something of a novice but understand the risks and safety aspects of the sport. I was planning to take my daughter to lake Windermere in the UK and try and paddle the full length over 2 days if the conditions are good. We will have shortie wetsuits and bouyancy jackets as the water temp is about 9 c that time of year. We'll be using decent sit on top kayaks and will have dry bags with about 20kg of gear each. Am I asking too much of her as the lake is 11 miles long so 5.5 miles paddling per day. She's fairly strong and very healthy.