Alexander, I would say that the sky is the limit. You have only trained for 3 months! Normally, runners develop over a 3 year time frame. If you look at the next 2 and a half years, you could plan out a training plan that will bring you to your goal. Just be careful, goals like yours don't come immediately. Hard work and good base building is the way to go. Also, your training should be long runs, with intervals, fartleks, and tempo runs. Do some research if these terms are unfamiliar to you.