I started skiing when I was 5 going on 6 and my brother was 4 1/2. The whole family started on the same day with a planned ski week. We went with another family who had similar aged kids and we all had lessons from the first day. We were very lucky that it was a small (in terms of people) very friendly field with a great community feel (basically 90% of the adults I knew very quickly - and they were all effectively parent substitutes in terms of safety/behaviour etc). I honestly don't have any recollection of my parents skiing in those early years - I spent all of our time with other kids my own age. We were never pushed to ski, if we wanted to spend the day mucking around by the huts then that was fine. This has certainly influenced how I introduced my now 4 year old son to skiing. While we now don't have the luxury of the small, big family/club field; and we now live a long way from ski fields, meaning that we only get a weeks guaranteed skiing a year, I have carried through three things from my experience. (My husband started skiing as an adult so has an entirely different experience). First is the importance of good quality, competent instruction - although I am more than capable of teaching my son to ski it was a conscious decision as I felt that excellent instruction made a huge contribution to the skier I am today. Second was being with a group of kids the same age - I loved tearing around the mountain with others the same age. And finally, but most importantly, the emphasis is on enjoying the snow. So, here is our experience - 1st year son aged 11 months - hated the childcare centre except when a parent was there - so husband and I had one run together and then spent the rest of the week taking turns to ski or hang out in the childcare centre with son (this bit was critical). Spent time with son in sled and building snow men. Second year 23 months - son perfectly happy in childcare - stuck with the sled, making snowmen, mucking around in the snow and a couple of runs between my legs - again lots of laughs. Third year, son 35 months, moved on from the infant childcare to three and four year old centre. Had a one hour lesson daily (but talked to the instructor and made it clear that if son didn't want to ski then we were happy for that to happen - in other words we weren't hell bent on "getting our monies worth" - son spent an average of 20 minutes per day skiing and had a lot of snowball fights. Third year 3yrs 11 months, same as year before but son very engaged in skiing and moved from the magic carpet to the poma/platter/button lift and loved it. We did swap instructors as son and first instructor didn't really hit it off - ended up with a young british guy who just clicked with son. In the afternoons we did some skiing together and took son up chair lift at the end of the week which he loved. We watched sons lessons from a long way away so he didn't know we were there - and to get a sense of what we should be reinforcing. All of these lessons were one on one and we deliberately chose our mountain for their kids programme rather than terrain for us.
We are now gearing up for year four and son has been itching to go skiing for months. He is booked into a programme that is a group lesson with similar age and skill children (max 3-4 in group) that gives him two hours in the morning and one hour in the afternoon, with the back-up of childcare if he goes off the idea of skiing.
This is what has worked well for us and so far son is hooked on skiing