The 28-year-old, hampered by a seven-week injury lay-off, ran a season's best 2:00.97minutes in New York on June 9 and in doing so claimed she's just getting going in her bid for one of three Olympic spots.
With selection for the 800m set to go down to the wire Simpson knows this weekend's Olympic trials in Birmingham hold the key - but with a pedigree of performing on the national stage she is more than confident.
The three-time British champion still needs to hit the London 2012 A standard of 1:59.90 but will line up against the likes of Marilyn Okoro and Emma Jackson, who have it, as well as Jenny Meadows knowing her Olympic dreams are still a reality.
"This is the one point in my life that I have been aiming towards," said Simpson - who failed to make it out of the heats of the 800m on her Olympic debut in Beijing in 2008.
"The Beijing Olympics were incredible, it was my first time and I was young and I wasn't developed so it was a case of running to the absolute best of my ability just to compete with the field.
"But since then I have gained so much strength, I am a lot stronger now to be able to cope and be competitive and get up there and really go for it.
"I'm getting there more and more each day and getting stronger. I haven't raced too much so far because my season started later because of injury, but I'm really looking forward to it and by the time the Olympics come around I'll be in my peak form.
"New York was my first proper 800m race, it's not ideal being so late, but you have to start somewhere. I can see that I'm starting to race near where I want to be, so it should set me up nicely for the trials and for the Olympics."
If the Newquay and Par AC runner does make it to London she insists the lessons learnt from her Chinese experience four years ago will be invaluable.
Simpson, who was at the opening of the new Holiday Inn and Staybridge Suites London-Stratford City overlooking the Olympic Park last Tuesday, admits mistakes were made but vowed to put that right in front of her home crowd.
She added: "Statistically most medallists come from their second Games, it takes that first one to bed yourself in.
"I remember Beijing being such an overwhelming experience that I almost forgot that I was racing, I made tactical errors because I was overwhelmed and that cost me getting to the semi-finals.
"This time around I won't make that mistake again because that is in the memory bank. You learn from these experiences and it gives you a better chance."