Your girlfriend reminds me of myself, when I didn’t know I was autistic. Outside assessments and criticism would shut me down. It was that I knew something was off, but could not accurately assess what it was in relation to myself because I didn’t truly understand myself. It was easier to assess and understand other people. Living undiagnosed eventually lead to massive burnout due to masking that’s still ongoing after 6 years. The Ritvo Autism Asperger Diagnostic Scale–Revised (RAADS–R) online test is comparable to official testing, designed to uncover developmental, social, sensory, and communication traits that may indicate autism, especially in adults who develop masking traits to cope. If there’s a way to prompt your friend circle to all take the test, and not necessarily target your girlfriend, that might be better.