She completed a graduate teacher programme with Reading university and Battle primary, also in Reading, after studying part-time for five terms.
And now the 45-year-old intends to be a supply teacher until she finds a permanent job.
More than half of all new teachers are like Ms McNamara and have changed careers to enter teaching, according to a survey.
She said: "I thought the GTP was a good way to go into teaching. Your eyes are wide open and you get so much more experience in schools. If it had been mostly university-based, I would be much more nervous about starting."
The study, by the Teacher Support Network, looked into how well new teachers were prepared to begin life in the classroom, and their hopes and fears.
It showed more than 50 per cent of respondents had switched careers and the majority were happy with their training.
More than 70 per cent of those surveyed cited workload as a prime concern, followed by bad pupil behaviour at 67 per cent, pressure to meet targets at 51 per cent, and money at 40 per cent.
Emily Hill, 28, a languages specialist, has just finished a graduate teacher programme in Cambridgeshire and is due to start at Hampton Vale primary, in Peterborough, this month.
She said: "Behaviour is one of my main concerns. If you can overcome behaviour issues early on, you can get on with just teaching the class."
For Joanne McCluskey, 24, workload was a major concern. She is about to start work as a PE teacher at St Leonard's school, Durham, and said she was concerned about the workload involved in writing reports and preparing for parents' evenings.
Ms McCluskey said: "I'm looking forward to getting paid, meeting other members of staff and the kids, and teaching without someone looking over my shoulder all the time."
Patrick Nash, the TSN's chief executive, said: "Pressures of the job can cause new teachers a great deal of stress if they do not have adequate support networks in place."
So far, the network has surveyed 54 people and it is inviting more new teachers to take part.