I took it waaayy to far ;( .......?

Okay,.....So about 2 weeks ago, I decided to "prank text" my cousin. I pretended I was this girl named veronica.... whenever I was bored, "Veronica" would text him. After a few days, Veronica and my cousin became friends (thats not even the bad part). I thought it was funny and planned to tell him I was Veronica, but I wanted to tell my friend about it the next weekend. So, Veronica and my cousin continued to text back and forth... Well, the weekend I saw my friend, some things happened (nothing nasty! My cousin hadn't even seen Veronica yet)...... and my cousin and "Veronica" ended up becoming bf and gf (wow)....... Of course, my friend thought this was hilarious, but my cousin still doesnt know that Veronica isnt real....... Im afraid to tell him now.... Hes sweet and everything to "Veronica". He told me that he likes Veronica alot (flinch)... Im afraid that if I tell him Im Veronica, he will be crushed and also maybe mad........ I just dont know what to do now.... Help!!! Should i wait until they break up or something?.... UGH!!! this is killing me!!!!!! Btw, my cousin is only 13....