I think you already have by being part of this programme!
I would suggest keeping your mind open to all the sciences early on and see which you like the most. Try hard at school and see what happens! Your could see if you could get some work experience is a lab/ go visit your closest univeristy.
You already are taking steps into a science career: you ask questions.
I had very little hands-on science experience after completing my undergraduate degree at university, so I did a lot of small internships in other labs – I went door to door asking if someone in the lab needed help to do small jobs and just watch around. Some said no, but many gladly opened the door. Little by little, you build your own stairs to go way up there: from an intern you become an assistant, then a technician, then a full time researcher. It takes time and persistence, and sometimes it will be boring, but you just have to keep building those stairs!
Find out what really excites you–is it understanding why animals behave the way they do? Why chemicals react in a certain way? How stars are born? Then find out more about it. When you find something you love to study, it hardly feels like work at all.
I think the first step is to work hard at school to get good marks and then get involved in voluntary activities related to science (like this one). In the future you can start a scientific degree in the university like Biology or Chemistry and then start a PhD. Then you will become a professional scientist :). I agree with Jonathan and Daniella that taking part in this is a very important step towards.
I agree with everyone else. If you think you’d like to be a scientist, try some hands on science. There are after school science clubs you could go to or look out for local science festivals -these are usually in bigger cities so it depends where you live. Often universities run these sorts of things. Find out what sort of science you like by trying different stuff. You might discover your inner geek!