No, it isn’t difficult as such to switch branches after the first year, as most of us are unaware of the syllabus and whether it is going to suit our caliber and interest at the same time. Owing to this many opt out of their initially chosen branch.
Make sure where your interests lie and look for scopes in the future. You can easily check about the vacant seats from your college department, consult your principal or administration as well for the best advice and help.