I have gap between my two front teeth.

The gap between the teeth can definitely be corrected by using braces, but I don't think such a treatment can be completed within 3 to 4 months. The duration of the treatment depends from case to case but you have to realise that we will not be moving only those two teeth but aligning all the other teeth to achieve a proper articulation, so you can expect the treatment duration to be somewhere around one to one and half years also keeping in mind your age because the bone density increases with age and teeth movement is slower. The exact treatment plan can be explained only by the dentist who has performed the clinical evaluation of the case and has seen the X-rays also. Please keep in mind that you need to have patience if you are going for orthodontic treatment because it is a slow treatment modality which gives permanent lifelong results. Regards