Taijiquan (Tai Chi Chuan) is a lifelong journey. It can take years to develop skill. That's why it helps to have a teacher who has skill and will coach you in a constructive way.
One of my goals as a teacher is to save time for my students and help them discover information that took me many years to learn.
Here is a video I made last week about a common mistake we all make until a good teacher tells us to stop doing it.
It's the problem of swimming knees. I encourage you to watch this video, then watch yourself in a mirror or record your own movement to see if it is something you need to work on.