As already said, how your parents react, will depend on their thoughts and beliefs ...... you're the only person on here to know the answer to that !!!!
Age gaps do work .... only 6 years between me and my missus though - she was 18 and I was 24 ..... and nearly 30 years later we're still together.
My sister in law was 20 when she started dating a 40 year old ..... that raised a few eyebrows. 30+ years together and 2 children, they were still together last year, when he sadly passed away in his 70's