My 4 year old had regularly walked and run from an early age, toddlers run everywhere! There is no danger to them, and it should be encouraged if she shows interest. My little boy ran a mile continuously the other day in 16 minutes, then walked a further 1.5 miles. I am of the opinion I'm his Mum & I'll decide if it's right or wrong, he could swim a width of the pool unaided at 2.5 and is brilliant now, go for it! Imagine her face when she gets a medal! Xx