It wouldn't hurt to go ahead and ask for LORs! Your recommenders will have to submit their letters electronically through Optomcas though, and I believe they are sent a little questionnaire to complete as well. Also would be good to have a list of all jobs, clubs, extracurricular activities, shadowing experiences, etc. that you'll want to add in your Experiences section. I think what I spent the most time was writing a personal statement, so I'd suggest starting a draft for that.