Ask HN: Rejecting client work at last minute

I’m a junior dev ( < 1 year ) and I was doing some work for a company, I vibe with the team and mostly do CSS ( which I love and they badly need it ), today they offered me a work contract for a year...the problem is I never thought they would give me a contract and started interviewing for another gig.

Despite the red flag of the junior profile the guys from the new gig chose me ( but no contract was signed ).

Problem is I signed today with the team I currently work with as I feel I need more stability and take my time to grow. But I can’t stop to think that I let the others down ( even if we speaking about a big 400 people company ).

I know it is just business and I shouldnt feel bad about it but how do you guys usually deal with situations like this ?