Tub Replacement

Hi there, I am planning to redo my master bedroom shower. Currently is is a plastic insert type and I plan to rip that out and tile it. My question is about the shower door. My opening is 48 1/4 inches. The shower seems to have been built for that plastic insert shower from the builder. When I went to Hope Depot to look for a new door none fit my dimension (most are 45" or 55"). So my question is, when you are getting a new shower door, can you buy one that is adjustable to fit your space, or do you get one custom made, or do you demolish or add to the space in the shower to accommodate a pre-made shower door? Wondering what options I have because depending on what is available I may or may not have to rip down a wall to make the new door fit. Thanks for any help in advance.

So my inquiry isn't necessarily DIY, since I am looking to remodel a bathroom and do not have the time, tools, or experience to pull it off myself without a major disaster. Hopefully someone has some experience and can chime in: I currently live in Southern California and am evaluating general contractors for a full bathroom remodel. I have found one general contractor who is licensed with the Contractor State Licensing Board (CSLB) and has very favorable reviews on Angie's List. I've met him in person and have a good impression, and believe he is offering a thorough and competitively priced bid. I've hit a red flag that's kept me from hiring him. He does have an active CLSB license, general liability insurance ($1mil policy), and contractor's bond for $12,500. What caught my attention is on the CSLB, it shows he does not have a worker's compensation policy because he is labeled as 'exempt' (meaning he has no employees which would require a policy). I asked the contractor about this and he said his 'workers' are covered with medical insurance. He used the term 'workers' but did not clarify if they were 'employees' or sub-contractors. I told him the workers compensation is a sticking point for me because I have family working in the field of civil law (court reporters) and they have seen many instances of workers comp. cases hitting the homeowner. He mentioned something along the lines of the contract that we'd sign would release me (the homeowner) of any liabilities. I am really unfamiliar with workers compensation laws and more specifically the relationship between the homeowner, the general contractor, employees of the general contractor, or sub-contractors of the general contractor. Everything else looks to be in-line, I just don't know if I am paranoid about the matter, or if I am right in being worried about liability. Does anyone have any experience with this topic or could provide some context for the matter? Thanks.