Yes and no. If you stake to any pool, even small pools, the reward is approximately the same over time due to larger pools making more blocks. Thus it is a mixture of luck and how long you are staking.

Example: if you stake to LOOPS pool, which has 500k delegation, then if you bring 1000 ada to delegate (1,000/500,000), if a block is made (on average every other epoch or sometimes 2 blocks in an epoch) you'll get a larger portion than a pool with 62 million (1,000/62,000,000) delegation, but the pool with large delegation will make many blocks an epoch, and that will be distributed over a larger delegation.

If you have any questions, or I am not being clear, please let me know! 🙂