Asalaamu alaikum, actually my dear sister it does matter that we get into the highest ranks of Jannah because the Prophet (Sallallahu Alaihi wasallam) said that we should ask for Allah in every dua for Jannatul firdaus for firdaus is the highest level of Jannah and if we fail to achieve it then it will be a source a great regret for us on the day of judgement, only because we had the opportunity in this world of making for ourselves an eternal place in the highest part of Jannah but instead we chased worldly pursuits and chose this world over the next. Choosing this world over the next is sacrificing a high place in Paradise.
Each level in Jannah is far from similar. One level higher is like a distant star and it is far superior than its lower level. So in order to gain it we must foresake any love we have for this world and live for the hereafter and do everything to please Allah and refrain from anything which angers or displeases him particularly the major sins and also have good intentions in everything we do and as you mentioned to be as sincere as we can be in our good actions.
Therefore we must strive to do everything to in this life to get a place there for ourselves and let NO ONE think it is not possible because our life until death is the opportunity to gain a place there. For the higher our place in Paradise the more we can see and meet Allah and there is NO greater reward in Jannah than with meeing Allah.
Therefore let our incentive be to earn the highest place in Jannah just so that we can see and meet with Allah more. What do we have to do to gain this and countless other pleasures for eternity? To sacrifice this world for the next and spend the little time we have in Allah's service. WHAT A BARGAIN!!!