。。
I know, I know. I've already thought about pacing myself, after all.
Literal
Understood [polite-わ]. Properly pace-distribution [topic-は] thought-about-[exists-てありますもの].
分かってますわ — ます + わ uses the feminine sentence-final わ. ペース配分 ('pace distribution') is a sports/strategy term applied to everyday life. 考えてあります uses the ~てある pattern for a state resulting from deliberate action ('I've thought it through and the result stands'). もの at the end adds feminine explanatory emphasis — 'because, after all.' The character is reassuring someone with composed confidence.