It is never too late to start gymnastics but there is a very limited amount of things you can teach yourself safely. Also people who self teach skills often have horrible technique which makes it impossible to build up to harder skills without having to first re-learn the existing skills. That usually takes a lot longer than learning completely from scratch because the bad technique gets ingrained in muscle memory.
If you are at all serious about wanting to learn gymnastics skills it would be much better to find a rec class. If you do try to teach yourself at home you can't really get past walkovers with any degree of safety.
You can learn splits at home, provided you follow good stretching protocols. I've answered questions about how best to stretch for splits on here loads of times so I'm sure you'll find that if you look. Basically the key is warm up thoroughly, go through preliminary stretches that stretch muscles you stretch in splits bit not all together like splits does, ensure stretches are gradual and controlled and hold at a point past comfort but before pain until your muscles relax (usually about 30 seconds.)
It's never too late:) It will be difficult, but if you want it bad enough, you can do anything. I recommend working on your flexibility and back flexibility first, look up YouTube videos to help you. Also, you'll need to condition to get more skills, again, look up YouTube videos for a gymnastics conditioning routine at home. Basically YouTube will help you a lot! Good Luck on everything :)
Stretch like crazy if you want to do the splits just Google Pinterest or you tube stretches for splits you'll get some good ones!!! Walkover practice walking your hands up and down a wall and bridge kick overs and handstand to a bridge and back bend kickovers you'll get there just work for it in a clear space that's matted also stretch so you don't pull something
No but it will be more difficult for you
