If you still sketch (and I’m guessing from your avatar that you do!) and no longer do robotics, I’d leave the sketching in. It adds a dimension (in part because it reinforces arts & humanities club and frames web design slightly differently – e.g. aesthetics as well as coding) in what might otherwise be read as a more exclusively STEM application. To me, your language skills, especially at your age, are as impressive as your math/science achievements but I’m a close reader of texts and I think it’ll be easier to miss this element in your application if you tilt the balance more in the STEM direction. To put this another way, while I wouldn’t privilege “well-rounded” over “STEM prodigy,” I think you have more of a “Renaissance man” vibe going on here and that is quite appealing, especially in a candidate who simultaneously looks (as another poster put it) focused.
Not a big deal either way – just a different opinion.