The 29-year-old is the reigning European Cross-Country champion.
She told BBC Radio Leicester: "I am sort of borderline going for marathon or 10,000m on the track, so that's the big question at the minute.
"We have now just got to have a chat with my coach and see where I am going with that."
Steel, who recently finished second at half-marathon distance in the Great North Run and was third at Sunday's Great Scottish Run, is yet to represent GB at an Olympics but sees marathon running as a long-term aim.
"I think the marathon is, in the future, where I could win a medal, but 10,000m on the track I am more comfortable with the distance.
"My coach is training me for the marathon, so I am prepared for it.
"I have only been going up to 15 miles in my training, but once I get comfortable with that and 17 miles, then 20, I think I will get more confidence."
Leicestershire runner Gemma Steel says she is yet to decide whether she will compete in the 10,000m or the marathon at the Rio 2016 Olympics.