This may be inapplicable to the advanced thinkers in here, but I, at 17 am learning about special relativity for the first time and i find that i am very slow at understanding the very basics of it. I have always been slow at grasping concepts because i like to be very sure in my thinking. I wanted to ask, how many people really understand special relativity, time dilation and other stuff related trully and fully? Because i think some people can articulate ideas, but dont really understand them, taking some concepts for granted, for example a 'simple' question like 'what is time?' can be answered seemingly competently but often lacks eveidence of understanding. I am aware i may be sounding unintelligent right now. I think i just need some material which explain things very basically (weblinks would e appreciated) so i feel confident i understand it. Peace.