I'd go with 10 to 3. Because then she can know that if the big hand is after half past, she can count backwards from the o'clock spot. Plus, you're teaching her on an analogue clock, so she can see, that the big hand is 10 minutes away from the o'clock. As she gets older, maybe you can get a clock you can write on and write 10, 15, 20, 25 etc all around the clock so that eventually she can learn that 2:50 and 10 to 3 are the same thing. But I'd go with analogue for now because I reckon that's what most kids learn first?