I would also suggest to try self trimming. It´s really not as hard as it sounds and if you have questions after reading Feye´s tutorial you know a place to ask.
If you do not want to selftrim, the idea with the Barber shop is very good. Preferably one with lots of experience where the owner still cuts hair like he did 40years ago when the shop opened. Far away from the inner city. Those are usually very relaxed places and they´ll do what their customers want, instead of what they think looks best. Good thing is that they are often much cheaper and do usually not insist on washing, blowdrying and "style" your hair, aka loading your hair with products and blowdry it in shape to hide what they just did. Stay away from every place which looks fashionable, fancy or modern in any way, usually is the safest bet.