Hi OP I am currently on a Clen cycle not too far through but it is my first so I will let you know how I get on, you will have to ask someone else about the age factor as I'm 27 so didn't really consider it in my research.
A lot of the side effects are due to the extremely high dosage that some people take, the cycle I'm doing is;
Clenbuterol 1 for 4 days, 2 for 4 days, 3 for 4 days, 4 for 4 days, 3 for 4 days, 2 for 4 days, 1 for 4 days
1 tablet is 20mcg of the ones that I have. You will also read a lot about cycling on and off but this can be avoided apparently by taking ketotifen.
Ketotifen 0 for 4 days, 1 for 4 days, 2 for 4 days, 3 for 4 days, 2 for 4 days, 1 for 4 days, 0 for 4 days
As you can see my cycle is 28 days continuously. I am quite a bit older and probably weigh more than you so if you were to try it I would recommend doing what my Mrs is doing which is go up to 3 clen and 2 ket and then back down meaning its a 20 day cycle.
Hope that helps but make sure you do your own research on the side effects and implications before ordering.
Another thing to add is when I ordered these and started discussing them on here a lot of people said that albuterol is better not sure why yet as that is my current research topic, anyone jump in???