My doctor told me that my ra is being controlled and its under remission. would it develop later or it will be stable?

See below: It is under control due to you taking methotrexate. However; it can wax and wane in activity and that is why you need continued followup with your rheumatologist to make that it is being controlled.

No one knows : There are no guarantees that remission will last a lifetime. It is encouraging that you are doing so well on Methotrexate alone. Takes each day as a gift. If a flare does occur there are other therapies such as tnf agents that are remarkably effective.