"For the first time, we have the opportunity to assume responsibility for the stability of this region," she told Bosnian BHT 1 television.
EU accession will contribute to the stability of Croatian institutions, she said.
"In the last 150 years, Croatia didn't have a state that lasted at least like the average human life," Pusic said, adding that the framework which stability provided in the long term was crucial.
She said that as of July 1, there would be no more customs on Croatia's western border and that this would give Croatian companies free access to a market of 500 million people.
Freedom of movement without obstacles is also important, although Croatia will have to wait to enter the Schengen area, Pusic said, adding that Croatians would be able to study anywhere in Europe for a quarter of the cost until now.
She voiced confidence that EU accession would be an additional incentive to investors to invest in Croatia.
Pusic said she strongly opposed the idea of a "two-speed" EU because that brought into question the Union's fundamental idea about lasting peace between the member states.
"The alternative is a greater level of integration," she said, recalling the discussions under way on how to equalize the financial and economic policies within the eurozone based on the experience of the member countries in the current crisis.
Pusic went on to say that Croatia was "absolutely prepared" for EU accession at the level of the EU's "average members" but with the ambition to achieve more and do better.
She defended the Croatian government's financial policy, saying it yielded results and that it was crucial to cut the state's costs. "There are symptoms that these policies work, but our main task remains to improve the investment climate."
Asked about problems with Bosnia and Herzegovina and the issue of connecting Croatia's south with the rest of the country, she recalled that a preliminary feasibility study financed by the EU showed that the best way to solve the issue was to build the Peljesac bridge and that now it remained to be seen if a financing model could be found.
She said the best solution was to use part of the EUR 11.7 billion in EU funds intended for Croatia in the next seven years because it eliminated the possibility of any corruption.
She described the idea of underwater tunnels as interesting but said nothing would come of it because the European Commission would make a decision based on the opinion of its consultants for the matter.
In the meantime, the issue of transit through Neum, Bosnia must be dealt with, Pusic said, adding that no solution would damage Bosnia and Herzegovina.
She said it was in the common interest of Croatia and Bosnia for the Ploce seaport, Croatia to be fully functioning, as agreed, and announced that the good neighbourly cooperation would continue after July 1, when Croatia joins the EU.
The TV reporter recalled that during the 1990s wars Pusic was among the few public figures in Croatia who spoke of the military aggression against Bosnia and Herzegovina, and asked what would happen if the International Criminal Tribunal for the former Yugoslavia (ICTY), in handing down a verdict for four former Herceg-Bosna officials, ruled that Croatia had been involved in the war in Bosnia.
Pusic said Croatia's universal position was to accept the ICTY's rulings. "Sometimes you like the rulings more and sometimes less, but that's part of what cooperation with the Hague tribunal or any other international judicial institution means."
She said her position on the war events had always been clear, then and now. "The HDZ (Croatian Democratic Union party) waged an aggressive policy towards Bosnia and Herzegovina," she said, adding that this position was a matter of continuity and a clear policy.