If the answer above is None it means there is no specific mention in the legislation, but you still need to ask local law enforcement before drinking in Bosnia and Herzegovina.
Selling alcohol to a minor under the age of 18 years is an offence. The law does not prohibit minors from buying, attempting to buy or consuming alcohol. Law on Public Peace and Order (2015) Article 25 prohibits providing alcohol beverages to minors. Law on Internal Trade (2010), Article 10 prohibits the sale in the retail trade of alcohol beverages to persons under 18 years of age.
You can find more legal details and links here:
Wikipedia Legal Drinking Page