I have taught an 80-year-old in secondary school and that does affect the dynamics of a class. A 25-year-old fits in much better," says Iain McGhee, head of the social studies faculty at Alloa Academy.
The 25-year-old in question is Ashfaq Rasul, who originally left the Clackmannanshire school in 1995. Although he achieved nine Standard grades, Ash was more interested in pursuing cricket and football and went on to play cricket at professional level in Australia and South Africa.
Now he is captain of Clackmannan County Cricket Club, which includes two other Alloa Academy teachers, and plays football for Corton Juniors.
"There's a guy in my football team I didn't know was a teacher till I saw him here on my first day back. I said: 'What are you doing here?' He said: 'I teach here. What are you doing here?' I said: 'Well, I'm a pupil.' " Ash chose to return to school rather than go to a further education college precisely because he knew some of the teachers.
"I don't feel awkward or embarrassed in front of the teachers or pupils.
Having played cricket in front of 4,000 people in South Africa and Australia, I don't embarrass easily and I'm here to get educated.
"I could have gone to Falkirk College but I wanted to come where I was known," he says. "Night classes were no use because I have to get my Highers at one sitting, and I didn't want to go to a school where I wasn't known and would feel out of place."
Ash has been doing four Highers (English, history, modern studies and physical education) and intends to take a law degree, hopefully at Heriot-Watt University. He is confident he will get the four B grades he needs.
"I think the idea of adult returners is a very good one," he says.
"People mature at different ages. A lot of 15- to 17-year-olds have other things on their minds besides studies and exams.
"I think it's good for schools, good for the economy and good for Scotland," he says.
It was his elder brother, who has a degree in business law, who instigated his return to school. When Ash came back from Australia, he sat him down and asked if anything was lacking in his life. When Ash said "Yes, education", he said "Go back to education, then." So, he did.
Ash comes from a family of high achievers. His father was a maths teacher in Pakistan and there is a doctor, a pharmacist and a chemical engineer among his siblings.
"Education has been very important in my family. My parents didn't force it on us, but it was valued," he says.
"Everyone is very welcoming here. I go to my classes, work in the library and go home in my car for lunch. So it's not really school for me," says Ash. "It's more like a second life. I don't have to ask for permission to do things.
"When I have a few drinks with my mates at the weekend, they have a good laugh at the idea of me as a school pupil but I know they're quite impressed really. They leave me alone to study when they know I have to."
If parental backing is vital in any young person's educational ambitions, financial security is also necessary. For three years Ash was a logistics manager for an international distribution company in Edinburgh, where he lived before returning to his parents' house.
"I'm mainly on consultation fees now because of school. The company were very keen that I returned to school and they are supportive. I was working nights and weekends until March but have only been working at weekends as the exams drew near. I'll continue to work for them when I'm at university," he says.
Alloa Academy headteacher Ralph Barker says: "Ash is unusual because he has financial means. The majority of people could not afford to do what he is doing.
"We'd welcome more returners but if the Government wants to get people back to school, they need to think of grants. Pupils from low income families on the new Education Maintenance Allowance scheme will be paid a small allowance to stay on at school from age 16 as from August this year. That in itself is good but there is a discrepancy here if they are paid and returners aren't."
The Government also needs to consider criminal office record checks on adult returners, he says, for the safety of other pupils.
"There is an issue with police checks which has yet to be resolved. Adult returners will have to be SCRO checked if they are to become commonplace. I think this is an issue which the Scottish Executive has to start looking into now as it is something that would have to be applied consistently across all local authorities."