She is currently studying at Manchester University for a degree in government and development, and can't wait to return to Uganda this summer to see students she taught during her gap year.
This will be the 21-year-old's fifth visit to Uganda in as many years. In 2001, when Nicola Davies was advertising the trip to Masindi Centre for the Handicapped, Ms Messham was studying her A-levels at Farnham college.
"I was one of the first to jump at the opportunity," she says. After two trips to the school, she decided to ditch her maths degree and defer her university place so she could work for international development charity Students Partnership Worldwide. She spent eight months teaching sexual reproductive health and condom use to students, aged 11 to 20, at a school in Bulopa, Kamuli District, central Uganda. "It was tough, but once I made relationships and realised how Ugandans operate, I started to get the message through."
She says her experiences in Uganda have taught her to make sure money doesn't rule her life. When she graduates she would like to work in healthcare policy at Christian Aid.