Our children went to school, on the train and then a bus from the ages of 10, 8 and 6 (by the time the 6 year old went, the oldest one was 13) but they were always together and with other older children travelling in a gaggle. Of course I worried about them, but it made them confidant from a very young age unlike their contemporaries who were delivered to the school gate by car and picked up in the same way and whose Mothers used to wave their hands in horror at the thought of letting their little darlings travel on, dare I mention it, Public Transport and alone! It obviously depends on where and when but you have to let go some time and I started by letting them go up to the village, then on the bus into the nearest town and then by train into Edinburgh - and this was before the mobile phone was de rigeur. There were rules which had to be adhered to and, thankfully, there were only a couple of occasions when things went a bit pear shaped (man threw himself in front of the train which was delayed some hours and snow and the wrong kind of leaves on the track) but they coped and were better for it. Every parent knows when their child is ready for the big outside world.