But Miss Jones - a Romany Gypsy by descent - believes it was the right choice and one that saved her from spending her school years staying at home "cleaning trailers and picking potatoes".
Miss Jones was recently elected as student representative for Funky Dragon, the young people's Welsh Assembly. She is also studying for an NVQ level 3 teaching assistant qualification at Pembrokeshire College. "My mum and dad always said I was not to go to comprehensive and, to be honest, I didn't feel safe to go. I had a real fear of being bullied," she says.
The unit at Monkton Primary opened in 1996 and educates 23 Gypsy and Traveller children of secondary age. Another unit attached to Tasker Milward Secondary in Haverfordwest educates more of Pembrokeshire's 202 Gypsy and Traveller children.
The county has five official Gypsy and Traveller sites - more than any other local authority in Wales.
Bev Stephens is head of Pembrokeshire's education service for Gypsy and Traveller children. She says Gypsy children often dropped out of secondary because the transition from primary was just too much to take.
"We started this initiative in Monkton 11 years ago because 25 per cent of pupils on the roll at the primary school were Gypsy and they were not going on to secondary," she told TES Cymru.
"Maybe one or two would go but then drop out. We built up trust and relationships with the families and they were happy for the children to stay on in a primary school setting."
The unit is a separate room within the infant site. Its pupils are integrated with primary pupils for assemblies and other school events. They follow the national curriculum with formal lessons in English, maths, IT and science.
Successfully educating Gypsy and Traveller pupils lies in a flexible approach, says Ms Stephens. "We've got to keep the curriculum relevant to them," she says. "Some of the boys have linked up with adult education to learn brick-building skills - they learn a lot of maths that way."
Other important differences include the way sex education is taught. "It has to be dealt with very tactfully," Ms Stephens says. "Gypsy parents feel it's taught too young in the comprehensive system and they don't feel it's the school's responsibility. If someone has a query, they can come to one of the learning assistants for a one-to-one to ask about it."
Attendance is also dealt with in a more relaxed way than in secondary school and it is not seen as truancy if families need to travel away for work, nor if pupils arrive late because they have to look after family members.
Staff at the unit also work hard to assure Gypsy parents that their children are safe from bullying.
"They need to know that there won't be prejudice and that their children will be respected," Ms Stephens explains.
She says the unit's flexible approach to discipline and the curriculum has helped reach its main goal - for Gypsy children to achieve qualifications to help them integrate into society.
"If I had a magic wand, all these children would be in secondary," says Ms Stephens. "But if they are failing in secondary school, integration won't be there later on. This is working and I don't see why we can't use this type of set-up for other groups of vulnerable children who find the gap between primary and secondary just too big. Secondary school is not for everyone - it is just too rigid."