Sophomore MM SA Networking for Junior Year BB???

I'm currently a sophomore and accepted a SA offer at a top MM bank. I'm not sure about the "norms" and everything because I'm still new to IB, but I ultimately want to end up at a BB for full time (so ideally for third year as well). Because IB recruiting starts so early and there are also so many early insight programs, is it okay to network for and apply to junior year SA somewhere different from my current bank? Of course assuming that I even get a return for junior year lol. Are you expected to stay or are you able to have some mobility as a second year? Not sure how to navigate around this - any advice/help would be greatly appreciated!