For Tai Chi I can only recommend a live instructor. There are too many details that you can't observe from a video or a website
Tai Chi isn't an easier form of training, and the skill and knowledge of your instructor is a critical part of your success.
Ask yourself which is better, Bad Karate instruction or no karate instruction. Well the case can be made in the same light for Tai Chi Chaun.
I'm not a believer in the short forms. I've practiced the Yang Long Fist 108 for 25 years, and recently have been studying the Wu Teaching Form (a more complex variation of the Yang). It tooke me 2 years to learn the form originally and a great deal of continuing work to progress into the study.
My own thoughts are the short forms are a short cut that really don't get into the depth of tai chi instruction.
But its a big world and everyone does as they wish. I can only offer my opinion.
Bushi No Te Isshinryu