I remember my boy being very interested in letters around that age - we had to read him the alphabet book every.single.night for his bedtime story or the world ended lol.

You can also get a letter sheet with the arrows and laminate it so she can write and rub off with a white board pen. I just got a Peppa Pig practice letters book that my girls like to use sometimes.

I would suggest you gently attempt to get them writing it the correct way before school though - my DS taught himself to write and allowed no input from anyone and now he forms his letters in a way that frustrates his teachers lol.