Celeste Coles, who lives in Birmingham, said ensuring a secure future for her 38-year-old daughter Rachel, who suffers from Down's Syndrome, would be one of her first priorities after scooping £3,665,079.
But she is also drawing up an ambitious list of travel destinations, with South America and the Rocky Mountains on the agenda.
Celeste, 69, only bought her ticket moments before sales closed ahead of the draw.
She said she knew she was in for something big when she checked her ticket at 11 o'clock on the night, and found she had matched five main numbers plus one Lucky Star.
She said she played the lottery occasionally, and decided to buy a ticket after receiving an email about the large Euromillions jackpot the afternoon before the draw.
"Remembering just moments before the sales closed I got myself a Lucky Dip ticket," she said.
"I didn’t think much of it and was about to go to bed when I remembered and thought I’d quickly check the draw results.
“One by one I ticked off the numbers, by the fifth main number I knew I’d won something big-ish, but then when I spotted I had also matched one of the Lucky Stars I knew I’d won something even bigger.”
Keeping a cool head, Celeste poured herself a glass of water as she contemplated her huge win.
“I’ve always been a pretty calm person, so there was no whooping from me, but I did decide a glass of water and a sit down was in order," she said.
"Now I think about it, I was probably in shock and I still am! You never think it will really happen to you.”
As well as Rachel, Celeste also has a 32-year-old daughter Nicola, who she contacted as soon as she found out about the win.
Celeste said Nicola questioned whether she was the subject of a scam after checking her numbers, but she was unable to contact lottery operator Camelot until the next morning.
"I didn’t sleep very much that night and called Camelot as soon as the lines opened," she said.
"When the win was confirmed I finally let myself believe it was all real.”
Celeste, who won the prize in July, already had a trip to her native Barbados planned so travelled to see her family soon after the money hit her bank account. Since coming back she has been busy planning how she wants to enjoy her winnings.
“The biggest thing for me is knowing that I now have financial security and that my girls will have a more comfortable life, especially Rachel," she said.
“I’ve always worked hard and now have a comfortable life, so there is nothing that I really want as such although I wouldn’t mind a holiday home in Spain, something I never thought would have been possible.
"I also have some trips that I’d love to take. I've always wanted to go to South America, so a trip to Rio, Chile, Brazil and Argentina are definitely on the cards.
"I’d also like to go on a train trip through the Rocky Mountains, that’s a real bucket list dream that I can now hopefully tick off in the not-too-distant future.”
Celeste said bringing up a daughter with Down’s syndrome had been challenging at times, but also rewarding.
She said one of the reasons she played the National Lottery was its support of Midland Mencap, which had helped Rachel to get a job and integrate into the community.
Nicola said she had been learning Spanish, and hoped to visit Mexico to practise the language, and Rachel said she hoped to be able to go on some cruises.