OP, I have a dd who is autistic and at uni. Her condition is such that it is also difficult for her to get a pt job, not just from a social interaction/processing information point of view but also in terms of motivating and organising herself. She does not have the maturity of an 18 year old and is much 'younger'. Dh and I manage all her accommodation and finances at uni and give her pocket money.
Does your dd have a formal diagnosis of autism? If she does, it is a good starting point.
My dd has both DSA and PIP. DSA is relatively easy to get. An assessor will review the paperwork, interview her and find out what her needs are. The assessor was lovely and did not try to catch dd out or quibble. DSA threw the support at her, including a laptop, printer, assistive tech (software to transcribe voice to text and vice versa), ASD support and Study Skills mentor. We also tried to get the uni to provide mental health support but they were a bit rubbish.
PIP on the other hand was very difficult to get. It took me, as dd's appointee, a total of 8 months, a stack of paperwork, one interview/assessment, 2 rejections, almost went to appeal tribunal before the DWP settled on an enhanced award of 400 pounds a month. DWP will back pay to the date of the application.
PIP is obviously worth it if you can get it for your dd because it is a cash award that can help bridge the financial gap. You say your dd is bright so she could be able to read all the tons of guides to help fit her condition within the exacting PIP criteria and argue her case in writing. There are also charities that have advisors to help advise on PIP applications. Most of the leg work is filling forms and submitting them within the deadlines. If your dd is unable to advocate for herself verbally (I am not sure how her autism affects her), you can do so for her by appointing yourself as her appointee if and when she needs to speak (during the assessment and during an appeal). My dd did not speak a word to anybody to get PIP. The great thing is I could absorb all that PIP stress on her behalf as her appointee and mother, hth.