OP yes talk to her and please know you have no idea what is going on in the woods, they could be going off on their own. They could be kissing and petting. It starts at this age. I would talk to her about all of it. Even if nothing's going on now (and I bet something is) she can put it to good use down the road).

I want to join the bandwagon and say it's imperative to be talking to her about this. Even back when I was a kid, my best friend was having sex at age 12 (with a 15 year old boy). Another friend had sex at 13 (with an 18 year old). And another friend got pregnant at age 13 (not sure who the father was). Guess where all this happened? The woods.

My sister worked at a respectable, popular, trendy, big box underwear store for several years. She said it was not uncommon to have girls who were clearly in junior high come in with their boyfriends and together pick out things like thongs, lacy underthings, etc. I am sure their moms had no idea and probably thought they were shopping at the mall with a group of friends and not on a "date" with a boy picking out sexy underwear.

I don't think you can assume a 12 year old's crush is innocent as even the good kids are faced with a lot of peer pressure and sexualization through media and friends.

I would be concerned about going off in the woods together unsupervised, even if it is with a group of kids. Because of her age I would think a new rule would be appropriate that opposite gender socializations must occur in open areas (living room as opposed to bedroom, cul de sac but not the woods, etc) and with easy access to adult supervision.

This is a tough one because I worked in middle school when my son was just starting 6th grade at age 11 and I was appalled to find out what was going on during school hours, let alone outside school. I would definitely keep a closer eye on where the two are going and what they are doing. Definitely have a talk with her about what is and is not appropriate if you haven't already.

I agree that neighborhood kids aren't going to tell.
Last year my DS had has first crush. He was 11. He and I are really close and we would talk about what they were doing and how he felt. I wa surprised at how open he was with this little girl about how he felt, especially when sharing his feelings as theynwere breaking up. Anyway, through our conversations I was able to tell what they were doing and make suggestions for what's going too far. He was actually relieved/happy to have me set guidelines. FWIW, I agree holding hands is fine. My son didn't get to kissing. Some of the issues we faced were whether they could go off together at school.

At 12, I would say holding hands is appropriate. Anything more is not, as it can quickly lead to other things.

I don't think the neighborhood kids would tell. I'm just sayin'.

DD (12) and a boy in our neighborhood like each other. They go on bike rides together incl into the woods where all the kids play. He is nice enough but I am sure they are both curios. Any advice on suggestions to give her or what is appropriate at her age? So far they have always had neighborhood kids with them who would tell if anything happened.