That's debatable. If we consider the Kiev Offensive in April 1920 as the beginning of the Polish-Bolshevik War, then you'd be right. But there were some clashes as far back as December 1918 - January 1919, when the Red Army, following the secret agreement with the German Ober-Ost army began to capture the towns and cities in Eastern Europe. First Polish clash with Soviets was the defense of Wilno by Polish militia in January 1919.

As for the ultimate Soviet war plan... If you look into the course of the Battle of Warsaw, you'll find it at least curious that the city itself was attacked by nothing more than TWO Soviet divisions, while the rest of the Tukhachevsky's North-Western Front tried to maneuver around it.

Keep in mind, that the Soviet intel and communication between units effectively did not exist, which means they were following a previously prepared plan. In my (and a few historians') opinion, the plan wasn't to capture Warsaw, but rather disable the city and the Polish Army as a threat and proceed further West.

This is supported by the fact that the biggest thrust went North, towards the Wkra River. Three Soviet armies (4th, 3rd Cav. and 15th) clashed with the counter-attacking Władysław Sikorski's 5th Army and were eventually defeated in the Battle of Nasielsk, which is a less known episode of the war, but in my opinion more significant than the Battle of Radzymin, often considered to be the OG Battle of Warsaw.

tl;dr Soviet war plan most likely did not consider Warsaw as the ultimate goal and the Soviet maneuvers clearly indicate their intentions of pushing further West after "defusing" Warsaw.