Speech therapy has no cure for a stutter but most speech therapist specialise in helping you feel confident that it's no crime to stutter but they'll give you some tips to try to reduce it. I think instead of practicing with yourself, try to rehearse it with a friend or two who's already aware that you stutter so it takes the pressure off you so it's not concealed as a massive secret. Whoever you practice with could let you know when you're talking a bit too quickly so they can politely interrupt you to keep to a much slower speed rate as talking fast can be a habit but habits can be broken. Maintaining eye contact with the person and trying to breathe can keep your body and mind relaxed. There are lots of other tips out there here or online but it's about finding a technique that works for you personally. If someone ever mocks you for it, don't stay in contact with ignorant people.