Did my training in Australia in 2002 and did first solo circuit after 11.3 hours - averaging about one flight a week. I still remember wondering if I was really ready because I was the first person that my instructor had ever sent solo.
It has been said before but I wouldn't worry about how long it takes you. Your instructor will send you when it is safe to do so and there are plenty of other considerations other than your ability that can affect this. Remember also that the training you do for your first solo will stay with you for the rest of your piloting life so it shouldn't be rushed. I have had many long gaps in my training since my first solo due to my job but I still find that what I learned back in 2002 comes flooding back fairly quickly as soon as I hop in the cockpit.
When it does happen the rush you get from that single circuit is more than worth the wait.