How do I tell my sister I’m pregnant?

She is 10 years older than me and has been trying for quite some time and has been going to see fertility doctors….I feel guilty telling her and I know she’ll be happy for me and she’s my best friend I just don’t know how to tell her without feeling awful. I feel very blessed that it worked for us our first try but still makes me feel guilty.

P.s I just found out yesterday but Like i said we’re super close and Ik she is going to want to know.