Which coffeshops are most leniant with enforcing the age restrictions, i know it's an inappropriate question but i'm not quite 18.
I some coffeeshops I get ID'ed as soon as I walk in (I don't look my age).. others don't seem to care. I guess it depends on the person behind the bar more than the specific coffeeshop.
15 is definately too young, unless you look WAY older and have the luck of not getting asked for ID.. then again you might want to consider if you want to even want to jeopardize the coffeeshop like that because if there is a control by the police and they find <18 year olds, the coffeeshop can get closed down.
There is a few I had no trouble getting into and I'm 16, sorry I can't remember the names but look around and you'll find somewhere.
the main issue here is not so much if you CAN do it, but if you SHOULD do it.. imho.. because it seems kinda disrespectfull that you ignore the rules in a country that is already soooo liberal when it comes to the marijuana policy. You risk the coffeeshop getting a fine or even being closed if they get a search for minors and they find you there.. I dunno.. I've been in a coffeeshop once when I was <18.. but looking back on it.. I dunno.. I really understand why you want to do it and what's nice about it.. and it's easy for me to be all moralistic about it now I'm 18+.. but at least consider the consequences of you being there as a minor..