Hilchos Bikkurim 10:17

First shearings are secular in all ways. Based on this, the Rambam maintains that they may be given to a woman of a kohanic family even if she’s married to a Yisroel, the same as with the gifts from slaughtered animals; the Rambam believes that the rules for these two gifts are the same.

Hilchos Bikkurim 11:1

There is a Torah obligation for every Israelite man to redeem his son when the son is the firstborn of an Israelite mother. This is from Exodus 34:19: “Every first issue of the womb is Mine.” Similarly, in Numbers 18:15: “You shall surely redeem the firstborn of a person.”