The 17-year-old 400m hurdler wowed the Olympic Stadium crowd in May with a time of 58.57 seconds, claiming a silver in the process, but fell just seven hundredths short of a qualifying time to make the big one in Barcelona.
McLean has one more chance to secure a seat on the plane to Spain at the England U20 Championships on June 16 and vowed to make up the difference.
While she admits that being so close to realising her ambition is tough to take, McLean insists she will go to Bedford full of confidence.
"I was really pleased with my PB at BUCS but it is so agonising," said McLean. "The qualifying time is 58.50 so I would prefer it if it was further away, or obviously to get the time, as with a time like that you don't know whether they will accept you or not, it makes you feel on edge.
"I have one more chance in Bedford to make the qualifying time. My coaches and I decided that it would be best for me to train hard for two weeks and go to the Under-20s fresh. So this is really my last chance to qualify for Spain.
"It's all about finding the right race and the perfect conditions, not raining and windy. I am trying to work on my stamina at the end; it is all about not getting tired."
McLean is one of eight talented young British sprinters taken onto Spar's Sprint Stars Programme for 2012 and she revealed she is already reaping the benefits.
As well as breaking personal bests this season, McLean believes following in the footsteps of 2010 Commonwealth Games 4x400m silver medallist Meghan Beesley can only be a good thing.
She added: "The Spar Sprint Stars is really helpful. The funding is helping me a lot. I have been able to travel abroad and train in different conditions which is something I wouldn't have been able to do.
"Training is going great at the moment, I just try to concentrate on myself and my own performance. I like taking one step at a time, and not getting too far ahead of myself."