According to a BYC survey of more than 1,000 11- to 25-year-olds, the EU referendum result of 2016 has left young people feeling uncertain about their future.
Half of those surveyed said they felt the world was changing for the worse compared with 35 per cent feeling it was changing for the better, with Brexit cited in follow-up focus group discussions, involving around 500 young people, as a key concern.
These discussions also highlighted fears that the Brexit vote had created "a platform for hate, racism and discrimination" in the UK.
Of those surveyed, 62 per cent said that they felt part of Europe. This proportion rises to 72 per cent among those in higher education.
The research findings have been presented to the government and EU policymakers, with the BYC calling for young people to have an active role in negotiations.
The BYC says this is particularly important as more than 1.5m 16- and 17-year-olds were unable to vote in the referendum.
"It is quite clear that young people continue to feel worried and uncertain about the future of our country following the EU referendum results, said Anna Barker, chair of the BYC.
"The government must ensure young people are centre stage of the Brexit negotiations going forward - so young people feel they have a real stake in their future."
The survey was carried out through the BYC's Young Ambassadors project, which aims to give young people a say in global decision making.
The survey also found that 53 per cent of young people felt they had limited opportunities to succeed in life. More than a third (37 per cent) believe gender inequality is holding them back and this is the main concern for the future among young people in Wales.
The BYC is calling for "high-quality citizenship education" to be made compulsory in schools to encourage participation in democracy and decisions that affect their lives.