http://www.mangago.me/read-manga/gokujou_no_koibito/
These three by Scarlet Beriko-sensei:
http://www.mangago.me/read-manga/joou_to_shitateya/
http://www.mangago.me/read-manga/amefurashi_shunu_ni_shippori_to_nureru_ooedo_renaitan/
http://www.mangago.me/read-manga/jealousy_scarlet_beriko/
(maybe this one too, not sure if same age or older)*shrugs* http://www.mangago.me/read-manga/yondaime_ooyamato_tatsuyuki/
Almost everything this author does has the seme as the younger MC. ლ(´ڡ`ლ) Just skim through them and find the ones you are looking for. http://www.mangago.me/r/l_search/?name=Naono%20Bohra
Any yaoi manga with a uke who is older than the seme but beautiful. The uke had his first sex with other guy than the seme?