Stopping breastfeeding at 1 years old

I weaned around 1 and just replaced each feed with a cup of milk or a cup of milk and a snack. I would definitely recommend doing it gradually one feed at a time to give your breasts a chance to reduce production or it can get painful.

was it a normal baby cup or a bottle?

Her and cups at the moment aren’t going well, she just spits everything out

Reduce day time feeds first, avoid sitting in the same spot where you usually nurse, if she comes to you distract her with a toy or book. No more nursing to sleep for daytime nap either.
Then get someone else to sleep next to her at night if you can so that she stops nursing

Replace the breast milk slowly with cow milk just pump in bottles but slowly replace more each few days with more cow milk. It takes only a month usually

I found sippy cups or straw bottles better accepted at 1. Maybe get her used to cows milk in the cup first and then night wean. You're not bring selfish, you've done great getting to 1!