As good a gesture as it may be and coming from good faith, people are normally sensitive about their privacy when it comes to such events. A free service as tempting as it may be, would also raise doubts in peoples' minds (general mind frame) about the authenticity and the skill of the photographer as these events occur rarely in a lifetime and people would want them to be covered 'professionally'. Since you are new to photography, I would recommend that you cover your family functions and perfect the skill there and then create a portfolio and start charging people based on that portfolio for covering their functions, minimally though. When you have a sample or portfolio of your skill, then you would be in a better position to convince people to cover their functions. Best of luck!