Job interview tomorrow but I’m not sure if I want it

I (19m) autistic person who recently left college due to creative disagreements with lecturers, I have a full time job at nights from 10-4am 5 days a week+ but I have applied for jobs that are more suited to the field I want to work in. One job that responded is really good ! It’s a well respected large scale tailors in my area the hours are Monday to Friday 9-6pm with a £1.50 pay increase which sounds amazing and is such a big opportunity for a 19 year old college drop out. I have a plan in place to apply to universities with a upscale perfected portfolio and this job would really help build my skills with it, my issue is that id have to quit my other job and work different hours to my partner (I know they shouldn’t be a factor in my future but I can’t help but factor them in some way). I’ve built a great rapor (sp?) with my current job they’ve helped me out a lot and bent a lot of rules for me my body has also taken to night shifts well but with my autism I can’t help but over think all of this. The job is a temporary position which is fine as there may be a chance of getting kept on but I will have to return to education at some point ultimately making my position a part time one or if the position is only for a couple months then I’d be throwing away a year of work and relationships with said work for £1.50 more an hour in a job which I’m unsure I’d like as everything is looked at so specifically and we’ll I’m not the most polished seamstress in the world and I also don’t want to be shoved behind a sewing machine all day. If I walk into this interview in 10 hours and I don’t like the environment, the boss or the vibe would I be a disappointment ? Would I be letting everyone down ? If I go into this interview will they give me time to think about their offer ? Or do they need an answer on the spot ?