Yes I will be upgrading to a 180 gallonWelcome to Fishlore.
People usually expect smaller tanks to last years, however you’re right to say it’ll only work for some months. Exactly how long depends on how big the fish are when you get them.
The answer to your question is yes, that is, only if you are absolutely certain you can upgrade to a big enough tank after the four months. If you don’t think you can upgrade in time, do the right thing and avoid keeping these 30cm+ fish altogether.