All perfect praise be to Allah, The Lord of the Worlds. I testify that there is none worthy of worship except Allah, and that Muhammad is His slave and Messenger.
There is no blame on you for going to Hadaa without being in the state of Ihram as long as you will return and enter the state of Ihram from miqaat of As-Sayl Al-Kabeer.
The basic ruling is that whoever passes the miqaat intending to perform the rituals at that moment or in the future, it is not permissible for him to pass the miqaat without ihram, unless he is going to return to the miqaat and enter ihram therefrom, in which case there is no blame on him for passing the miqaat without ihram.
Haashiyat al-Jamal (a Shaafi’i book) reads: “But if he passes it intending to return to it, or to the same distance as he did before wearing ihram in that year, then he does not sin by passing it if he returns.”
Allah knows best.