I started training on a 152, at 25 hrs I decided to change to a 172 as im 6'2 and comfort was an issue especially as I was starting longer flights on navigation exercise's.
it cost me 2 hours of extra training before being allowed solo on the 172, then 45 minutes of solo circuits before I continued with nav ex's.
I feel a lot more comfortable in the larger aircraft and it was what I intended flying when I get my licence anyway so in terms of hours ive lost nothing but the cost has increased.