No, you are not limited to a certain number of characters.
An SMS message can have up to 160 characters including 'space' and 'enter'.
For SMS messages above 160 characters, the length of 1 SMS message changes to 153 characters. For example, if your message has 320 characters, your campaign will be sent as 3 SMS messages (153+153+14 characters).
On Step 3 of your SMS creation, we indicate the number of characters used and the number of SMS required for sending your message.