As a female you will be judged more stringently than if you were a male. Some female TV reporters, especially the more attractive, often have a bad reputation even when they do not deserve it.
You do not say which country you are living in, so it is more difficult to answer your question. I will be general in my answer.
At High School --
(a) Try to join the school newspaper and if they have a radio or TV station, join their team and work on that.
(b) Make sure that you are excellent in English plus look at subjects like "legal studies" so that you can do "Law Reporting", "Court Reporting" and "Police Rounds" and even several of the "political rounds -- local, state and Federal. Other subjects are politics and social studies or political geography. These will help you with political reporting. History is always a good subject to study as it helps with several areas of journalism. If you are thinking of becoming a "Foreign Correspondent" then languages, history of where you would like to work plus their culture and politics etc are essential.
(a) Buy the best dictionary you can. I suggest the "Complete Oxford English Dictionary" (the two volume edition not the 13 volume). This will do you through High school and through university and then into later work as a journalist. This has both the British and US spellings plus the origins of the words.
(b) Telephone or write to the local main Metropolitan newspaper and ask for a copy of their "Style Guide". This will give you an idea of how the paper wishes you to write your stories, which words to avoid and which words are misused etc.
(c) Ask the local suburban newspaper if you may write some articles for them and later progress to larger newspapers and magazines. Even if you wish to do broadcast journalism (radio and TV), you still need to know how to write a story and collect facts etc.
(d) Learn to pronounce your words clearly.
At College/University --
(a) Either do a Media course or a journalism course later specialising in "Broadcast journalism".
(b) Join the university's newspaper and if they have a radio or TV station, then join that and do as much reporting as you can.
(c) Contact your local TV station early during your university course and ask if you may do some casual work for them, going out with other reporters and TV cameramen and seeing what they do and how they cover a story. Later they would then ask you to do some of the reporting both off-camera then on-camera. By the time you have finished your course, you should be able to move straight into a staff position.
A former TV news cameraman and journalist with over 30 years in the industry in Australia and Southeast Asia.
Currently a SE Asian historian.