Live in Pembs but Aberaeron area is like a second home. Had a caravan there for 20 odd years. Dont think I can recommend any beaches as they are all small and will be very crowded.
What I can recommend is that you come back when things are quieter so you can enjoy all the small beaches already mentioned.
Honey ice cream on the Quay is a must as Delmbox says. Pricey but worth it.