DSA will not impact you whatsoever, so do not let that deter you from pursuing your dreams. Your DSA application is made directly to Student Finance England and with your consent shared with your university to ensure the supportive measures are implemented to help you throughout the duration of your course.
Each student will be assessed independently by Occupational Health after enrolment to determine if they are fit to practice and have the appropriate support in place to minimise any adverse effects on the students health and on the setting they are allocated their placement within. Occupational Health is mostly about supporting you, so I would try not to worry and be as open and honest as you can to ensure the right support is provided to you.
If it’s any reassurance to you, this is my second degree I am also studying Mental Health Nursing in September at London South Bank University and I previously had a successful legal career with a Masters in Law. I have a diagnosis of ADHD and I have disclosed this in advance to the university and they have been nothing but supportive.
I hope that helps and I wish you all the best!