My husband is 4 years younger than me but we have never experienced any disparities in terms of maturity level, thinking or personality. I had dated younger men before I knew my husband too (just happened they were younger - i didn't specifically date just younger ones). I don't think age can ever be a barrier because I have seen much older men who behave immaturely so it still boils down to the personality of the man, rather than his age. The only difference I see is only in terms of job and income as I have worked many more years than him so my earning power is naturally higher but he has a great job and a good pay too so there's really no worries as he has a career path ahead of him to carve his niche.