Hello, Fapnewbie. Are you and your roommates reasonably close and good friends and you know they will understand the discomfort and pain you will have, perhaps help you during recovery and do things such as grocery shop for you, maybe pick up a prescription, pick you up from hospital if you had general anesthetic, heat up soup, food, or make a cup of tea for you?
If you are perfectly okay with them and others knowing about you and your pouch, then you could be okay sharing the apartment. You could put all your supplies in the bathroom in a plastic storage bin with lid, or a covered basket, for your own privacy and ease of access, or keep it in your own room. When I had my temporary ostomy bag I had a schedule: I would shower before breakfast (when the stoma and house was at it quietest and my stoma was not shooting out food and waste) and I changed my ostomy bag in my bedroom where my supplies were already laid out on the bed in the order I needed to put them on. I did this every three or four days, a complete change, but more often if it leaked. I learned to change the bag in under 10 minutes, but it took a week or two to get this down pat. So, you might not need to perform your bag changes in the bathroom -- unless your stoma is very active and spitting. You might just need the bathroom a lot AFTER your takedown when your new j pouch will be very active, 10 or 12+ times a day. Be prepared that when you change your ostomy bag it will need to be taken to the trash, outside, if possible, because it will be messy and smelly. My used ostomy bag always went into a plastic bag, sometimes double-bagged, knotted securely, and taken to the outside trash so no smells lingered in the bathroom and the house did not smell at all. I had a small supply of cleansers, disinfectants, bathroom Lysol wipes, collected plastic grocery bags, paper towels (for the spitting stoma!). This kept the bathroom and toilet rim clean.
Have you told your roommates about your upcoming surgery? I only told a few people I trusted completely because I am the shy type when it comes to something like this. I printed a diagram of it off the internet so they would see it and have an understanding. It's less mysterious and confusing that way. It all depends how much you need your privacy, how much they (and perhaps guests) can handle, and can you count on their discretion, now, and in future, if that matters to you. It can be an awkward, mysterious, painful, messy, uncomfortable process, taking at least a year from first surgery to recovery after takedown. It's a major surgery and big change. On the other hand, you might welcome the company and comfort of close friends. If you do upgrade to an apartment with private bath, it might only take a year longer to have your finances together for a house. Do what feels best for you, financially and personally.