Take care of chores and responsibilities around the house properly and early. Then when given a chance, talk to them. Contrary to popular belief parents are in fact humans, they tend to listen and understand when treated as such in a mature responsible manner. Explain, the puzzle(s), the solve, and how much you enjoy it. Show them that it's not just a random holiday trick skill that's going to be gone and replaced by something new next month. Show them the websites you frequent, the new puzzles you're interested in (and not just the more expensive 3x3's, but the more complicated puzzles that will require you to understand and learn in order to solve). If you can show them that this is a hobby that you truly are invested in, that you want to become very successful at, then there's a good chance that you will open their eyes and they'll give you more freedom in when you can do it. Especially if you can show them that you're still willing and able to take care of other responsibilities along the way, such as house chores and school work.