In 1162 she was asked for her hand in marriage to Floris III, Count of Holland (c. 1132–1190) by the Abbot of Egmond, Holland. Together, the Abbot and Ada traveled back to Holland, where the wedding ceremony occurred, probably in Egmond, on 28 August 1162. Ada received the County of Ross in the Scottish Highlands as a wedding gift.
Ada was not actively involved in the governance of the County of Holland but was occasionally mentioned in documents. Floris, her husband was a loyal ally of the Holy Roman Emperor, Frederick II, and often went with him into battle. Dutch chronicler Melis Stoke states that she supported her son in the war with William of Cleves during the War of Succession. In addition, Ada is known to have read Latin. Ada died after 1206 and was probably buried in the Abbey of Middelburg, to which she had already made donations of £64.
Ada and Floris had 8 or 10 children, of whom some died young, including the following issue: