I started researching my family tree when I was a teenager. Mainly stemmed from my maternal grandfather's cousin's tree which I saw when I was younger. He's done quite a lot over the years. I've done other branches on my Mum's side of the family as well as my Dad's side. When I started I talked a lot to my three surviving grandparents (my fourth had died when I was little). They were all supportive that I was taking an interest. I asked for lots of information, including all the family stories. Also talked to various great aunts and uncles and gained even more information. I have spoken to most of my generation and older generations over the years.
After I got married, I talked to my ex husband's family and got a lot of information as well. Even though I've been divorced for several years now, I still do the odd bit of research on my ex's family (for the sake of my girls - so they know their roots better).
I've had several people ask me why I don't restrict myself to just to my blood lines. I answer - like seeing where the research takes me even if it's people who don't share the same blood line as myself, it's interesting to see where the research can take me. So far I've got connections to all the continents except the Antartic. I've got blood relatives who were born, lived, married, worked, died and/or buried on all the continents apart from one!! Not bad. Still got blood relatives of mine around the world.
Also through my research, I managed to put my Mum and I back in contact with one branch of the family that we hadn't had any contact with for almost 100 years. My Mum's paternal grandparents split up when my Grandpa was little. We knew almost nothing about his Father's side of the family, until I stumbled across a family tree website using what I knew. We are now back in contact. It's sad that my Grandpa never knew that he had more family that he knew about. Sadly, a lot of information that we may have wanted to know, has died with the people who knew it.
Certainly found that researching famiy history can be fun and interesting. I haven't had a lot of objection/wondering why I do it. Actually found it interesting when I was talking to some of my cousins, I found that I knew more of the family stories than my cousins put together. Our mutual grandparents really enjoyed the fact that I sat down with them (as a teenager) and was prepared to listen to their stories - however many times I was told them.
Yes certainly school is important, but doing family history is a project/hobby that can be picked up on/left for periods of time. As someone I know said - the dead aren't going anywhere!!! You never know where it may lead you.