Yes. I'm 40 and most of the time I would say I'm reasonably fluent. I wouldn't say I "cured" my stuttering but have found tools and techniques that are a tremendous help. I've never seen a speech therapist as an adult but have found self-help methods work for me. The key for me is to find ways to reinforce fluent speech, especially when I find myself slipping back into stuttering. For example I read out loud to myself, talk to myself (especially in the car when I'm alone), "copy" the people talking on the radio or TV, etc. When I'm in a period of fluency my brain feels different, so I'm trying to reinforce those neural pathways. Keep at it and don't give up!