Apply for internships in those fields. Does not have to be the exact position you want.
F.e. it should be easier to get an internship as a draftsman than an architect without any degree. Draftsman often work together with architects so you would get a good feeling of the work you might have to do.
If you already want to start studying you could go for civil engineering and switch to architecture later. The best outcome would be if you get into an university that offers both civil engineering and architecture and that has some of the same subjects in both studies. That way if you switch from one to the other you can transfer your credits.