Alfred is no stranger to the process of accepting new members of the Family, at this point. Bruce seems to pick up a new one every couple years or so - and that is not a complaint. Alfred has felt deep joy at watching Bruce open his home and heart, watching the family grow. It's become more than he'd ever dreamed. It's wonderful.
And yes, most new members come with trauma. Bruce certainly has a sort of person he looks for when choosing to take in someone new - a certain genre of life experiences. It's understandable - the man experienced it himself, naturally he sees young ones going through similar sorts of pain and can't leave them unaided. Bruce has a big heart. Alfred is proud of him for this.
And the thing is, usually teaching the newcomers to deal with their pain and stress and trauma is part of the gig. Bruce usually handles the more, ah, physical side of catharsis; exercise is good for the body and soul both. Alfred usually takes on the other side of the coin - helping newcomers find or continue fulfilling hobbies. Encouraging Cass's ballet, Tim's photography, Jason's love of reading... that sort of thing.
So really he should be thankful you came with an established, healthy coping mechanism. A hobby you enjoyed and found soothing. And he is! Truly. Better yet, he understands, for it is a hobby he shares in common!
Yet he is still finding it slightly vexing to allow an untested, new member of the family into his domain of the Manor - the kitchen. Bruce tells him you love to cook and bake - so of course, you shall! It's just... well... Alfred has witnessed enough kitchen disasters come from this family to be a little protective of his space, alright? It's nothing against you. He's sure you'll do wonderfully. But he... is... going to observe. Oversee. At least this first time. Just in case.
So Alfred has taken up a seat in the kitchen, where he can watch you work, and has staunchly told himself he will only get involved if it is requested of him or in the event of a disaster.