But Marissa Porter's mind has been robbed of those precious moments.

In March, at the age of 26, Ms Porter was diagnosed with multiple sclerosis - a disease of the central nervous system.

MS has already taken a toll on her memory, and she now walks with the help of a bright pink walking stick, but it hasn't dented her determination.

On Sunday, the Farmborough Heights woman will tackle the annual MS Walk and Fun Run at Sydney Olympic Park, which raises money to support people with multiple sclerosis.

"I know I'll be in pain at every step, but I'm going to just push through," she said.

"I'm sticking it to the MS."

On Wednesday, Ms Porter, on leave from her role as a carer at IRT Five Islands, and her four-year-old son Alex visited the residents and her colleagues for a morning tea fundraiser, which collected $239.

The young mum was first hospitalised last October with symptoms that doctors thought was heart-related.

But earlier this year those symptoms and some new ones, including left-sided weakness, stuttering, slurred speech and collapse, returned.

Eventually she was diagnosed with relapsing-remitting MS - a form of the disease that can be inactive for months, or even years, before returning.

"I was relieved because I thought, MS, it's not that bad, it's not terminal, I'm not going to die from this," she said.

"But as the symptoms got worse and hung around longer and when I did more research I thought, this isn't that awesome, it's maybe not the relief that I originally thought it was."

Although well-versed in diseases that strike the elderly, MS had never been on her radar.

"I didn't know anyone who had MS, had never met anyone who had been diagnosed with MS, I didn't even know what MS meant," she said.

That has quickly changed and Ms Porter is now trying to spread awareness of the disease.

To donate visit mswalk.org.au, click on donate and search for Marissa Porter.