Accounting student is right, Giovane.
Usually preceded by the article "an" as in "I am/he is...an accounting student". And as a mnemonic device (a memory device) you can think of accounting firm (firma de contabilidade), accounting processes (processos de contabilidade), etc.
Could be an accounting graduate, for example, or a high school accounting student perhaps.
Or we could say: accounting students at both high school and college level.