Silicone, definitely. If it's your first time with anal play then you're going to be very tight, you're not going to have experience with relaxing yourself enough on demand, and it's possible that your body will involuntarily clench against the toy, so you want a nice soft material which will cushion any of that and feel comfortable as you get used to playing around.
I'm fairly new to anal toys! Which is the winner? Keep in mind I may not go with these sizes in particular, I am just asking regarding the material.
When new to anal, I would always suggest SOFT toys early. Work your way up to more rigid toys. I also am a big believer in SMALL and SLENDER first toys....take it slow and easy (YES, flanged toys, made for anal), but honestly, I have seen some "beginner" toys I would not and COULD not take in my tush after 40 years of frequent anal play!!!!
Ok, material aside, please don't listen to any of these people. Yes, for anal toys you want to go silicone, however, The Big End is not a beginner toy. If you're looking for you're first anal toy go with the Small End or another similar sized toy.