It depends upon what you mean by "formally".
Back in the day,most of us went to Technical College Night School.
Those lucky enough to be able to score an Apprenticeship got Day release for some subjects,but mostly did Night school like the rest of us.
The old Department of Civil Aviation & PMG's Department (later Telecom Australia) had excellent internal training systems,as did some other organisations,but mostly it was Tech School for the rest.
The big organisations used to have Cadet Engineers-----you could go to Uni,& be supported by the employer.
In your breaks from Uni,you were put to work,officially supervised by a Senior Engineer,but more likely you would go & work on your project amongst the Techs & "Get the edges knocked off you".
Some Techs also got into this system after completing their first year of Uni "under their own steam."
Alas,such Cadetships have pretty much disappeared,so you will probably have to do it all yourself.
In the present climate,I would suggest that there are two possibilities:
(1)
At 15, you still have some years left in Secondary School,& should try to get the best results you can get in your Year 12 Exams.
That way,you have a fair chance to get into University,where with HECs funding & a lot of hard work,you can get your Degree.
(2)
The other route,is to do a Certificate,and/or Diploma at TAFE.
In my opinion,TAFE courses today do not give you as good a grounding in your chosen subject,as the old Tech Colleges did.
The emphasis seems to be on "outcomes",so that you finish the course able to do some particular things.
This is all well & good,but it doesn't encourage the versatility needed by a good Tech,so some independent study would be a good idea.
You MAY be able to get an Apprenticeship,so will be given study days & so on.
If you end up with a Technician's job,& after a while are established financially,you could then decide to go to Uni as a Mature Age student,& get your Degree,
The downside I see with (2),is if you are doing OK as a Tech,making reasonable money,& having maybe by then,a wife & kids,plus a Home mortgage,
the "I wanna be an EE" idea will be "put on the back burner,& you won't end up doing it.
I realise this advice sounds funny coming from a Technician,but I think (1) is your best bet.