Assalamualaikum - I married but my family doesn't know (male)

Assalamualaikum, I'll be straight - earlier this year I was going through a rough patch and, after talking a lot with a sister I met, we decided to make our relationship halal and married even though it was our first meeting. Alhamdulillah so far it has gone okay. Her family agreed and my family only knew I was planning to marry. We were messaging often and, to avoid fitna, we chose to do nikah quickly. In my culture we usually have the families meet first and then do the celebrations, but I pushed for the nikah and planned to have a later celebration where my family would think the marriage was happening then. I don't think my parents would have outright refused, but they might have made it complicated with objections or traditions I didn't want, so I thought making it halal right away was best. I live in another country for half the year, and the guilt is getting to me - my parents have treated me well and I feel a bit like I've betrayed them. I hoped they'd be the kind of parents to accept and support the marriage, but I'm worried if I tell them, especially my mother and siblings, there will be drama. I want to tell them soon but I don't know how to approach it. How serious is this sin-wise in Islam? Please make dua that it goes well and that I handle this correctly. For context: I'm 27+, financially independent.